TANDEM AMINATION CATALYSIS IN THE SYNTHESIS OF DIAZAPHENOXAZINE COMPOUNDS OF PHARMACEUTICAL INTEREST

ABSTRACT

The synthesis and characterization of five new linear diazaphenoxazine compounds is reported. The key intermediate, 3-chloro-1-9-diazaphenoxazine, was prepared via a base catalyzed reaction of 2-amino-3-hydroxypyridine with 2,3,5-trichloropyridine in aqueous 1, 4-dioxane.

Five 3-amino derivatives of the key intermediate were prepared via Buchwald – Hartwigamination coupling reaction between 3-chloro-1,9-diazaphenoxazine and various heterocyclic amines, under the catalytic influence of palladium acetate.

The assignment of structures to the synthesized compounds was done by the use of combined information from Uv-vis, IR, and NMR spectra.

 

TABLE OF CONTENTS

Title page…………………………………………………………………………………………………….i

Approval page………………………………………………………………………………………………………ii

Certification…………………………………………………………………………………………………………iii

Dedication……………………………………………………………………………………………………………iv

Acknowledgement………………………………………………………………………………………………..v

Abstract……………………………………………………………………………………………………………….vi

Table of contents………………………………………………………………………………………………..vii

CHPTER ONE…………………………………………………………………………………………………………1

1.0  Introduction…………………………………………………………………………………………….…….1

1.1 Background of study………………………………………………………………………………….……3

1.2 Statement of the problem………………………………………………………………………….…..5

1.3 Objectives of the study…………………………………………………………………………………..6

1.4 Justification of the study………………………………………………………………………………..6

CHAPTER TWO…………………………………………………………………………………………………….7

2.0  LiteratureReview………………………………………………………………………………………….7

2.1  TandemAmination and Amidation………………………………………………………………..7

2.2  LinearPhenoxazines……………………………………………………………………………….……19

2.2.1  Non-azaanalogues of phenoxazines…..……………………………………………….…..20

2.2.1.1Benzo[b]phenoxazine……………………………………………………………………………..20

2.2.1.2   2-Amino-4,4α-dihydro-4α,7-dimethyl-3H-Phenoxazine-3-one………………22

2.2.2       Aza analogues of phenoxazines……………………………………………………………23

2.2.2.1         1-Azaphenoxazine……………………………………………………………………………24

2.2.2.2         2-Azaphenoxazine……………………………………………………………………………27

2.2.2.3        3–Azaphenoxazine……………………………………………………………………………28

2.2.2.4        4–Azaphenoxazine……………………………………………………………………………33

2.2.2.5       3,4-Diazaphenoxazine……………………………………………………………………….34

2.2.2.6       1,4-Diazaphenoxazine…………..…………………………………………………………..35

2.2.2.7       1,9-Diazaphenoxazine ………………………………………………………………………37

2.2.3           Nitro, Amino, N-Acetyl and N-Alkyl Phenoxazines…………………………….38

CHAPTER THREE………………………………………………………………………………………………..42

3.0        Experimental……………………………………………………………………………….…………42

3.1       General Information……………………………………………………………………………….42

3.2        3-Chloro-1,9-diazphenoxazine………………………………………………………………..43

3.3         Preparations of Single Crystals of 3-Chloro-1,9-diazaphenoxazine ………..43

  1. 4 1,4-Bis(2-hydroxy–3,5–ditert–butylbenzyl)piperazine…………………..………..44
  2. 5 General Procedure for the Synthesis of 3-AminoDerivativesof 1,9-Diazaphenoxazine……………………………………………………………………………………..……….44
  3. 5. 1 3-(2-Amino-3–nitropyridino)-1,9-diazaphenoxazine……………………………..45
  4. 5. 2 3-(2–Aminopyrazino)–1,9–diazaphenoxazine……………………………………..45
  5. 5. 3 3-(2-Aminopyridino)–1,9–diazaphenoxazine……………………………………….46
  6. 5. 4 3–(2–Aminophenyl)–1,9–diazaphenoxazine………………………………………..46
  7. 5. 5 3–Anilino-1,9–diazaphenoxazine………………………………………………………..46

CHAPTER FOUR …………………………………………………………………………………………………47

4.0       Results and Discussion ……………………………………………………………………………47

4.1        3–Chloro–1,9-diazaphenoxazine ……………………………………………………………47

4.2        1,4–Bis(2–hydroxy–3,5-ditert–butylbenzyl)piperazine …………………………..49

4.3       Catalyst Preactivation …………………………………………………………………………….49

4.4      3–(2–Amino-3–nitropyridino)-1,9-diazaphenoxazine ………………………………49

4.5      3–(2–Aminopyrazino)-1,9–diazaphenoxazine…………………………………………50

4.6      3–(2–Aminopyridino)-1,9–diazaphenoxazine………………………………….………..51

4.7       3–(2–Aminophenyl)–1,9–diazaphenoxazine………………………………….…………52

4.8         3–Anilino–1,9–diazaphenoxazine………………………………………………..…………52

CHAPTER FIVE ……………………………………………………………………………………………………54

5.0   Conclusion …………………………………………………………………………………………….……54

REFERENCES…………………………………………………………………………………….…..55

 

 

LIST OF FIGURES

Fig 1:Uv-visible spectrum for 3-(2-amino-3-nitropyridino)-1,9-diazaphenoxazine……………………………………………………………………………………………….66

Fig 2:Uv-visible spectrum for 3-(2-aminopyrazino)-1,9-diazaphenoxazine………….67

Fig 3:Uv-visible spectrum for 3-(2-aminopyridino)-1,9-diazaphenoxazine…………..68

Fig 4:Uv-visible spectrum for 3-(2-aminophenyl)-1, 9-diazaphenoxazine…………..69

Fig 5:Uv-visible spectrum for 3-chloro-1, 9-diazaphenoxazine …………………………..70

Fig 6:Uv-visible spectrum for 3-anilino-1,9-diazaphenoxazine…………………………….71

Fig 7:IR spectrum for 3-chloro-1,9-diazaphenoxazine………………………………..……….72

Fig 8:IR spectrum for 3-(2-amino-3-nitropyridino)-1,9-diazaphenoxazine…………..73

Fig 9:IR spectrum for 3-(2-aminopyrazino)-1,9-diazaphenoxazine………….…………..74

Fig 10:IR spectrum for 3-(2-aminopyridino)-1,9-diazaphenoxazine…………………….75

Fig 11:IR spectrum for 3-(2-aminophenyl)-1,9-diazaphenoxazine……………………….76

Fig 12:IR spectrum for anilino-1,9-diazaphenoxazine………………………………………….77

Fig 13:1H-NMR Spectrum for 3-chloro-1,9-diazaphenoxazine……………………………..78

Fig 14:1H-NMR Spectrum for 3-(2-amino-3-nitropyridino)-1,9-diazaphenoxazine……………………………………………………………………………………………….79Fig 15:1H-NMR Spectrum for 3-(2-aminopyrazino)-1,9-diazaphenoxazine………….80

Fig 16:1H-NMR Spectrum for 3-(2-aminopyridino)-1,9-diazaphenoxazine…………..81

Fig 17:1H-NMR Spectrum for 3-(2-aminophenyl)-1,9-diazaphenoxazine……………..82

Fig 18:1H-NMR Spectrum for 3-anilino-1,9-diazaphenoxazine…………………………….83

Fig 19:13C-NMR Spectrum for 3-chloro-1,9-diazaphenoxazine…………………………….84

Fig 20:13C-NMR Spectrum for 3-(2-aminopyrazino)-1,9-diazaphenoxazine…..…….85

CHAPTER ONE

1.0   INTRODUCTION

Phenoxazine(1) is a compound analogous in structure to phenothiazine(2) with oxygen in place of sulphur.Its other systematic names are 10H-phenoxazine and 2,2,5,6-dibenzo-1,4-oxazine1.They are tricyclic nitrogen-oxygen heterocycles2. Owing to the wide range of application of phenoxazine compounds, the synthesis of their derivatives and isolation of the natural phenoxazines have been a subject of great interest over the years3. Phenoxazine compounds have a wide range of applications, particularly as drugs and dyes.

 

The naturally occurring phenoxazine derivatives have been classified as Ommochromes, fungal metabolites, Questiomycins and Actinomycins4.

Phenoxazines are generally grouped into linear phenoxazines and angular phenoxazines. The linear phenoxazine, as the name implies, has a linear arrangement of rings like compounds 3 and 4 below.

 

payment

SYNTHESIS OF NHETEROARYL SUBSTITUTED

 

 

CHAPTER ONE

1.1       INTRODUCTION

The basic sulphonamide group –SO2NH- occurs in various biological active compounds including antimicrobial drugs, antithyroid agents, antitumor antibiotics and inhibitors of carbonic anhydrase1,2.  Sulphonamides are widely used to treat microbial infection by inhibiting the growth of gram-negative and gram-positive bacteria, some protozoa and fungi3. Clinically, sulphonamides are used to treat several urinary tract infections and gastrointestinal infections4. Sulphonamides that are aromatic or hetroaromatic are responsible for the inhibition of the growth of tumor cells. They act as antitumor agents by inhibiting carbonic anhydrase. Sulphonamides are structurally similar to p-aminobenzoic acid (PABA) which is a cofactor that in needed by the bacteria for the synthesis of folic acid. Sulphonamides antibiotics inhibit the synthesis of purine and DNA in the microorganism. Sulphonamide antibiotics are used as veterinary medicines to treat infections in livestock herds5,6. Sulphonamides are extremely useful pharmaceutical compounds because they exhibit a wide range of biological activities such as anticancer, anti-inflammatory and antiviral functions7-11. The sulphonylation of amines with sulphonyl chlorides in the presence of a base is still being used as the method of choice because of high efficiency and simplicity of the reaction12. However, this approach is limited by the formation of undesired disulphonamides with primary amines and by the need of harsh reaction conditions for less nucleophilic amines such as anilines13. Additionally, side reactions take place in the presence of a base. Sulphonamides have been used as protecting groups of OH or NH functionalities for easy removal under mild conditions14-15. In recent years, molecular iodine has been extensively used for a plethora of organic transformations as an inexpensive, nontoxic, readily available catalyst under very mild and convenient conditions to afford the corresponding products in excellent yields with high selectivity16-22. This can be seen in the case of efficient molecular iodine catalyzed method developed for preparing sulphonamides (Scheme 1).

 

payment

 

SYNTHESIS, CHARACTERIZATION AND PHARMACOLOGICAL STUDIES OF 4-ACYLPYRAZOLONE COMPLEXES OF SOME d-BLOCK ELEMENTS

CHAPTER ONE

1.0       Introduction

Investigation on 4-acyl-3-methyl-1-phenyl-1H-pyrazol-5(4H)-one (4-acylpyrazol-5-one) and its transition metal complexes has attracted significant attention because of their applications as extractants1, antipyretic2, analgesic3, antitubercular4, antimycobacterial5, antibacterial6, antifungal7, and antineoplastic8 drugs. 4-acylpyrazol-5-one, is an enolizable ligand with strong ligating ability. These ligands are synthesized by direct acylation at C – 4 of 3-methyl-1-phenyl-1H-pyrazol (4H)-5-one (PMP) with acyl chloride or anhydrous pyridine in dioxane at reflux9. 4-acylpyrazol-5-ones are phototropic isomers forming ketoenol, diketo-, and aminodiketo tautomers10. These features of tautomerism imbues them with several coordination modes11 (O, O-donors, O, N-donors, O-donor) and easily form coordination compounds with virtually all the elements in the periodic tables. This ligating ability is more predominant with transition elements because of increased bonding orientation associated with the d-orbitals. Owing to their high extracting ability, lower pKa values (in comparison with acetylacetone, (acac), and thenoyltrifluroacetone, (HTTA), great separation power, intense colour of complex extract, and low solubility in aqueous medium, several workers have used 4-acylpyrazol-5-ones to extract metal ions12. Based on their ligating properties they are also used in the spectrophotometric determinations of several metal ions such as Fe(III)13, V(VI)14 UO22+15 Mo(IV)16, Ni(II)17, Co(II)18, Mn(II)19, V(IV)20, Cr(VI)21, Ca(II)22, Zn(II)23, Mg(II)24. 4-acylpyrazol-5-ones such as acetyl-(HPMAP), propionyl-(PMPrP), Butyryl-(HpmBuP), isobutyryl-(Iso-HPMBuP), benzoyl (HPMBP), valeroyl (HPMVP), isovaleroyl- (HPMisoVP), caproyl (HPMCP) trifluoroacetyl (HPTFP), and trichloroacetyl-(HPTCP)25 have been synthesized, spectroscopically characterized, and used in diverse applications that cut across medicine26, biology27 and pharmacology28.

 

Because of their thermal stability29 these functionalized ß–diketones are used as molecular precursors in chemical vapour deposition techniques and in fabrication of polymer light-emitting diodes for low-cost, full-colour, flat-panel displays30. The magnetic and electronic properties of ß-dikotonates are also used in liquid crystals display and supramolecular assemblies31. As catalysts in hydroformylation and hydroboration, 4-acylpyrazolonates are used as spectator donors32 for intermediate species in organic reactions. Investigation of coordination compounds of lanthanide ions has been done by several worker owing to their fluorescent broad applications in biochemistry33, materials science34, and medicine35. 4-acylpyrazol-5-ones with a pyrazole nucleus share structural features with some pyrazol-5-ones derivatives (metamidozole, phenazone or antipyrine, dipyrone, edaravone) that exhibit as analgesic, antipyretic and anti-inflamatory activity36. Because of its promising antipyretic and analgesic activity, these drugs are used for treating fever and flu-like infections37. Edarovone (3-methyl-1-phenyl-2-pyrazolin-5-one) which has close resemblance to 4-acyl-pyrazol-5-one is used in the treatment of brain ischemia38 and myocardial ischemia39. Also, because of pyrazole functionality, 4-acyl pyrazolone exhibit cytoxic activity against bacterial40 and fungal pathogens41 and cancer cells42.

 

1.2       Statement of the problem

Though Jensen’s method of synthesizing 4-acylpyrazol-5-one using conventional heating method supplanted the method used by Claisen 100 years ago43, it still posed a great environmental problem44. These methodologies, although utilized for the preparations of a variety of pyrazol-5-ones, often require the use of refluxing conditions and lengthy reaction time, ideally 2-3hrs45. Moreover, the use of excess and often costly solvents and their recovery can pose a major environmental problem46 especially in the large-scale synthesis. Due to the increased environmental consciousness throughout the world, extensive efforts have been developed as an alternate synthetic approach for biological and synthetically important compounds. The microwave-assisted one-pot synthesis47 is one of the areas where substantial progress will be directed. Again, the scourge of infective diseases and increased pathogen resistance48 by bacterial and protozoal microorganism to existing drugs and in continuation of our search for biologically active molecules has necessitated the urgent need for novel drugs49 for treatment of Malaria and trypanosomiasis in human beings and cattle50. These devastating effects have called for alternative, effective regimen of chemotherapy51. Moreso, environmentally hazardous pesticides and insecticides used in our farms call for benign alternatives52. Keeping in view of these limitations of existing drugs we synthesize acylpyrazolonates that is both efficacious and bereft of blighting of our medicinal herbs in the farms.

 

1.3       Objective of the study

The debilitations and health hazard caused by exposure to pathogen such as bacteria, fungi, plasmodium, and trypanosomiasis, have necessitated the synthesis of drugs that will be used for effective treatment. The specific objective of the study therefore is to:

 

payment

SYNTHESIS, CHARACTERIZATION AND SOLVENT EXTRACTION STUDIES OF 3,5-BIS[(2-HYDROXY-BENZYLIDENE)-AMINO]-BENZOIC ACID AND ITS Co(II) AND Ni(II) COMPLEXES

CHAPTER ONE

INTRODUCTION

 

1.0     General Introduction

Extraction is the transfer of a solute from one phase to another. Common reasons to carry out an extraction in chemistry are to isolate or concentrate the desired analyte or to separate it from species that would interfere in the analysis. The most common case is the extraction of an aqueous solution with an organic solvent that are immiscible with and less dense than water; they form a separate phase that floats on top of the aqueous phase1.

Solvent or liquid-liquid extraction is based on the principle that a solute can distribute itself in a certain ratio between two immiscible solvents, one of which is usually water and the other an organic solvent such as benzene, carbon tetrachloride or chloroform. In certain cases the solute can be more or less completely transferred into the organic phase. The technique can be used for purposes of preparation, purification, enrichment, separation and analysis, on all scales of working, from microanalysis to production processes. In chemistry, solvent extraction has come to the forefront in recent years as a popular separation technique because of its elegance, simplicity, speed and applicability to both tracer and macro amounts of metal ions2.

The ability of a solute (inorganic or organic) to distribute itself between an aqueous solution and an immiscible organic solvent has long been applied to separation and purification of solutes either by extraction into the organic phase, leaving undesirable substances in the aqueous phase; or by extraction of the undesirable substances into the organic phase, leaving the desirable solute in the aqueous phase.3

 

1.1     Background of Study

Although solvent extraction as a method of separation has long been known to the chemists, only in recent years it has achieved recognition among analysts as a powerful separation technique. Liquid-liquid extraction, mostly used in analysis, is a technique in which a solution is brought into contact with a second solvent, essentially immiscible with the first, in order to bring the transfer of one or more solutes into the second solvent4. The separations that can be achieved by this method are simple, convenient and rapid to perform; they are clean as much as the small interfacial area certainly precludes any phenomena analogous to the undesirable co-precipitation encountered in precipitation separations.

Solvent extraction has one of its most important applications in the separation of metal cations. In this technique, the metal ion, through appropriate chemistry, distributes from an aqueous phase into a water-immiscible organic phase. Solvent extraction of metal ions is useful for removing them from an interfering matrix, or for selectivity (with the right chemistry) separating one or a group of metals from others4.

Solvent extraction is one of the most extensively studied and most widely used techniques for the separation and pre-concentration of elements. The technique has become more useful in recent years due to the development of selective chelating agents for trace metal determination5

 

1.2     Scope of Work

The Scope of this research is limited to synthesis of the Ligand Bis(salicylidene)3,5-diaminobenzoic acid, its Co(II) and Ni(II) complexes, spectrophotometric characterization via UV, IR, H and NMR(1H and 13C), extraction of cobalt and nickel metal ions in water using chloroform as organic solvent and separation of Ni(II) from aqueous mixture of Ni(II) and Co(II).

 

payment

SYNTHESIS AND EVALUATION FOR BIOLOGICAL ACTIVITIES OF NPYRIDIN

ABSTRACT

In this study, a series of N-pyridin-3-yl substituted [phenylsulphonamido] acetamide has been synthesized. The reaction of phenylsulphonyl chloride with various amino acids in basic medium yielded phenylsulphonamido alkanoic acid which, on chlorination with thionyl chloride, gave acid chloride derivatives of phenylsulphonamido alkanoic acid in situ. The acid chloride derivatives on condensation with 3-aminopyridine gave corresponding acetamide in good to excellent yield. The compounds were characterized by FTIR, 1H-NMR and 13C-NMR and screened for antibacterial, antifugal and antioxidant activities. The result revealed that the compounds possess antibacterial activities.One the compounds, 2-[(phenylsulfonyl)amido]propanoic acid had better antibacterial activities than ciprofloxacin the reference drug  while others are less active. All the compounds has less antifungal activities than ketokonazole the reference drug. 2-[(phenylsulfonyl)amido]propanoic acid had the best antioxidant properties of all the compounds.

 

 

 

TABLE OF CONTENTS

Title page    –        –        –        –        –        –        –        –        –        –        -i

Approval page     –        –        –        –        –        –        –        –        –        -ii

Dedication  –        –        –        –        –        –        –        –        –        –        -iii

Acknowledgement         –        –        –        –        –        –        –        –        –        -iv

Abstract      –        –        –        –        –        –        –        –        –        –        -v

Table of contents  –        –        –        –        –        –        –        –        –        -vi

CHAPTER ONE

  • Introduction      –        –        –        –        –        –        –        –        -1

1.1.       Background of the study      –        –        –        –        –        –        -1

1.1.1.    Chemistry and nomenclature of sulphonamides         –        –        –        -11

1.1.2.    Medicinal important or sulfonamides     –        –        –        –        -12

1.2.       Statement of the problem or research question –        –        –        -16

1.3.        Objective of the research     –        –        –        –        –        –        -17

1.4.         Justification of the study    –        –        –        –        –        –        -18

 CHAPTER TWO

Literature review

2.1.     History of sulphonamide drug discovery  –        –        –        –        -19

2.2.     Synthesis of sulphonamides –        –        –        –        –        –        -21

2.2.1.   Synthesis from amination of chalcones    –        –        –        –        -26

2.2.2.   Chloromethylsulphonylation of benzylisothiourea               –        –        -26

2.2.3.   Copper ii oxide catalytic sulphonylation method        –        –        –        -27

2.2.4.   Synthesis from ionic liquid mediated approach –        –        –        -28

2.2.5.   Synthesis from heteroaryl thiols     –        –        –        –        –        -29

2.3.      Sulphonamide as antimicrobial agents     –        –        –        –        -29

CHAPTER THREE 

3.0.    Experimental section     –        –        –        –        –        –        –        -31

3.1.     Materials and method   –        –        –        –        –        –        –        -31

3.2      Synthesis of benzensulphonamide   –        –        –        –        –        -31

3.2.1.   Synthesis  [(phenylsulfonyl)amido]acetic acid   –        –        –        -32

3.2 .2   Synthesis of  4-methyl-2-[(phenylsulfonyl)amido]pentanoic acid  -32

3.2.3    Synthesis of  2-[(phenylsulfonyl)amido]propanoic acid –               –        -33

3.2.4    Sythesis of 3-phenyl-2-[(phenylsulfonyl)amido]propanoic acid     –        -34

3.2.5     Synthesis of 4-(methylsulfanyl)-2-[(phenylsulfonyl)amido]

butanoic acid    –        –        –        –        –        –        –        –        -34

3.3.   General method of synthesis of N-heteroaryl substituted

Benzensulphonamide       –        –        –        –        –        –        –        -35

3.3.1    2-[(phenylsulfonyl)amido]-N-(pyridin-3-yl)acetamide –        –        -36

3.3.2.   4-methyl-2-[(phenylsulfonyl)amido]-N-(pyridin-3-yl)pentanamide.         -36

3.3.3.   2-[(phenylsulfonyl)amido]-N-(pyridin-3-yl)propanamide     –        -37

3.3.4.   3-phenyl-2-[(phenylsulfonyl)amido]-N-(pyridin-3-yl)propanamide         -38

3.3.5.   5-(methylsulfanyl)-3-[(phenylsulfonyl)amido]-N-(pyridin-3-            yl)pentanamide. –          –        –        –        –        –        –        –        -39

3.4        Biological activities    –        –        –        –        –        –        –        -40

3.4.1    Antimicrobial activity –        –        –        –        –        –        –        -40

3.5.      Evaluation of antioxidant activity  –        –        –        –        –        -40

3.5.1.    Scavenging of dpph radical  –        –        –        –        –        –        -41

3.5.2      Reducing power        –        –        –        –        –        –        –        –        -41

3.5.3.    Ferrous sulphate induced lipid peroxidation scavenging     –        –        -42

 

CHAPTER FOUR

4.0       Results and discussion          –        –        –        –        –        –        –        -44

4.1       Benzene sulphonamides        –        –        –        –        –        –        –        -44

4.1.1    [(phenylsulphonyl)amido]acetic acid       –        –        –        –        –        -44

4.1.2.   4-methyl-2-[(phenylsulfonyl)amido]pentanoic acid     –        –        -45

4.1.3     2-[(phenylsulfonyl)amido]propanoic acid,       –        –        –        –        -46

4.1.4.    3-phenyl-2-[(phenylsulfonyl)amido]propanoic acid   –        –        -47

4.1.5.    4-(methylsulfanyl)-2-[(phenylsulfonyl)amido]butanoic acid          –        -49

4.2.       Synthesis of  N-pyridine-3-yl substituted benzensulphonamide    –        -50

4.2.1.     2-[(phenylsulfonyl)amido]-N-(pyridin-3-yl)acetamide        –        –        -51

4.2.2.     4-methyl-2-[(phenylsulfonyl)amido]-N-(pyridin-3-yl)pentanamide        -51

4.2.3.     2-[(phenylsulfonyl)amido]-N-(pyridin-3-yl)propanamide   –        -53

4.2.4.     3-phenyl-2-[(phenylsulfonyl)amido]-N-(pyridin-3-yl)propanamide       -44

4.2.5      5-(methylsulfanyl)-3-[(phenylsulfonyl)amido]

N-(pyridin-3-yl)pentanamide         –        –        –        –        –        –        -56

4.3       Biological activities.    –        –        –        –        –        –        –        -57

4.3.1    Minimum Inhibitory Concentration(MIC) mg/ml        –        –        –        -57

4.3.2    Results of sensitivity test      –        –        –        –        –        –        -59

4.4       Anti oxidant evaluation        –        –        –        –        –        –        –        -60

4.4.1    Invitro free radical scavenging effect of samples by dpph method -60

4.4.2.   Ferrous sulphate induced lipid peroxidation     –        –        –        –        -62

4.4.3    FRAP       –        –        –        –        –        –        –        –        –        -63

CHAPTER FIVE

5.1.    Conclusion –        –        –        –        –        –        –        –        –        -64

5.2      References –        –        –        –        –        –        –        –        –        -65

 

CHAPTER ONE

INTRODUCTION

1.1 Background of the study

The growing incidence of microbial resistance to currently used antibiotics represents a serious medical problem. Therefore, there is an urgent need to develop new classes of therapeutic agents to treat microbial infectious. Such new therapeutic agent has to exhibit a wide spectrum of biological activities. Sulphonamides, an important class of pharmaceutical compounds, exhibit a wide spectrum of biological activities1. The basic sulphonamide group [SO2, NHR] occurs in various biologically active compounds including antimicrobial drugs, antithyroid agents, antitumor, antibiotics and inhibitors of carbonic anhydrase2 . Sulphonamides are widely used to treat microbial infections by inhibiting the growth of Gram negative and Gram positive bacteria, some protozoa and fungi3 . Clinically, sulphonamides are used to treat several urinary tract infections and gastrointestinal infections4. Sulphonamides5 that are aromatic or heteroaromatic are responsible for the inhibition of the growth of tumor cells. They act as antitumor agents by inhibiting carbonic anhydrase activity. They are structurally similar to p-aminobenzoic acid  (PABA) which is a cofactor that is needed by the bacteria for the synthesis of folic acid. Sulphonamide antibiotics inhibit the conversion of PABA into folic acid and thus ultimately inhibit the synthesis of DNA. They are also used in veterinary medicine to treat infections in livestock6. In primary care medicine, sulphonamides are widely used in various conditions including gastrointestinal7 and urinary tract infections8. Sulphonamide is the organic framework of main focus in this research and it belongs to the family of suphur-containing compounds9, which are earlier referred to as sulpha drugs . Some of these sulpha drugs that have performed “healing magic” in the world of chemotherapy include; sulphanilamide(1), sulphadiazine(2), sulphacetamide(3), sulphamonomethoxine(4), sulphasalazine(5), sulphadoxine(6), among others. Sulphonamides have long been the subject of pharmaceutical interest as a result of their potent biological activities10

payment

SYNTHESIS AND CHARACTERIZATION OF ZINC OXIDE NANOWIRE

CHAPTER ONE

INTRODUCTION

1.1 Background of the Research

Nanoscience evolution and the advent of nanowire fabrication marked a new epoch in optoelectronics 1. Characteristic investigation for achieving efficient light absorption, charge separation transport and collection had culminated in the synthesis of both organic and inorganic semiconductor nanowires 2-3. The d-block transition elements of the periodic table are all metals of economic importance. Zinc, which is a group II element, finds numerous potential applications, such as smart windows, solar thermal absorber, optical memories and photoelectrocatalysis 4-5.

Nowadays, the products of semiconductor industry are spread all over the world and deeply penetrate into the daily life of humans. The starting point of semiconductor industry was the invention of the first semiconductor transistor in 1947.3 Since then, the semiconductor industry has kept growing enormously. In the 1949’s, the information age of humans was started on the basis of the stepwise appearance of quartz optical fiber, group III-V compound semiconductors and gallium arsenide (GaAs) lasers. During the development of the information age, silicon (Si) keeps the dominant place on the commercial market, which is used to fabricate the discrete devices and integrated circuits for computing, data storage and communication. Since Si has an indirect band-gap which is not suitable for optoelectronic devices such as light emitting diodes (LEDs) and laser diodes, GaAs with direct band-gap stands out and fills the blank for this application. As the development of information technologies continued, the requirement of ultraviolet (UV)/blue light emitter applications became stronger and stronger which is beyond the limits of GaAs. Therefore, the wide band-gap semiconductors such as gallium nitride (GaN) and zinc oxide (ZnO), i.e. the third generation semiconductors, come forth and turn into the research focus in the field of semiconductor.

ZnO is a typical II-VI semiconductor material with a wide band-gap of 3.37 eV at room temperature. Although its band-gap value is closer to GaN (3.44eV), its exciton binding energy is as high as 39eV, which is much higher than that of GaN (25eV). Therefore, theoretically, we can harvest high efficient UV exciton emission and laser at room temperature, which will strongly prompt the applications of UV laser in the fields of benthal detection, communication and optical memory with magnitude enhancement in the performance. Moreover, the melting point of ZnO is 19540C, which determines its high thermal and chemical stability. Again, ZnO owns a huge potentially commercial value due to its cheaper price, abundant resources in nature, environmentally friendly, simple fabrication processes and so on. Therefore, ZnO has turned into a new hot focus in the field of short-wavelength laser and optoelectronic devices in succession to GaN in the past decade.

It is believed by many researchers that ZnO is a more prospective candidate for the next generation of light emitters for solid state lighting applications than GaN, even though the GaN-based LEDs have been commercialised and currently dominated the light emission applications in UV/blue wavelength range. This is because ZnO has several advantages compared to GaN. The two outstanding factors are;

  1. The exciton binding energy of ~39eV at room temperature is much higher than that of GaN (~25eV), which can enhance the luminescence efficiency of ZnO based light emission devices at room temperature, and lower the threshold for lasing by optical pumping. 6-7
  2. The growth of high quality single crystal substrates is easier and of lower cost than GaN.6-7

Increasingly interesting properties and potential applications of ZnO have been discovered. One of the most attractive aspects is that it is relatively simple for ZnO to form various nanostructures including highly ordered nanowire arrays, tower-like structures, nanorods, nanobelts, nanosprings and nanorings 8. Due to the special physical and chemical properties derived from the nanostructures, ZnO has been found to be promising in many other applications, such as  sensing 9-10, catalysis 11-12, photovoltaics 13 and nano-generators 14-16, just to mention but a few.

In order to utilize the applications of nanostructure materials, it usually requires that the crystalline morphology, orientation and surface architecture of nanostructures can be well controlled during the preparation processes. For ZnO nanostructures, although different fabrication methods such as vapor-phase transport 17, pulsed laser deposition 18, chemical vapor deposition and electrochemical deposition,19 have been widely used to prepare ZnO nanostructures, the complex processes, sophisticated equipments and high temperature requirement make them very hard for large-scale production for commercial application. On the contrary, aqueous chemical method is of great advantage due to much easier operation and very low growth temperature (950C) 20. ZnO nanostructures grown by this method show poor orientation and different crystalline structures due to the fact that, the optimum conditions required for the growth of these nanostructures is still grossly understudied. Hence, it is still a significant challenge to obtain controllable growth of ZnO nanostructures. It is therefore imperative to investigate the various conditions necessary for the growth of well align ZnO nanostructures.

1.2. NANOWIRES

A nanowire is a nanostructure, with the diameter of the order of a nanometer (10−9 meters). Alternatively, nanowires can be defined as structures that have a thickness or diameter constrained to tens of nanometers or less and an unconstrained length 21. At these scales, quantum mechanical effects are important — which coined the term “quantum wires”. Many different types of nanowires exist, including metallic (e.g., Ni, Pt, Au), semiconducting (e.g., Si, InP, GaN, ZnO, etc.), and insulating (e.g., SiO2, TiO2).

Typical nanowires exhibit ratios (length-to-width ratio) of 1000 or more. As such they are often referred to as one-dimensional (1-D) materials. Nanowires have many interesting properties that are not seen in bulk or 3-D materials. This is because electrons in nanowires are quantum confined laterally and thus occupy energy levels that are different from the traditional continuum of energy levels or bands found in bulk materials. Peculiar features of this quantum confinement exhibited by certain nanowires manifest themselves in discrete values of the electrical conductance. Such discrete values arise from a quantum mechanical restraint on the number of electrons that can travel through the wire at the nanometer scale 21.

Nanowires also show other peculiar electrical properties due to their size. Unlike carbon nanotubes, whose motion of electrons can fall under the regime of ballistic transport (meaning the electrons can travel freely from one electrode to the other), nanowire conductivity is strongly influenced by edge effects. The edge effects come from atoms that lay at the nanowire surface and are not fully bonded to neighboring atoms like the atoms within the bulk of the nanowire. The unbonded atoms are often a source of defects within the nanowire, and may cause the nanowire to conduct electricity more poorly than the bulk material. As a nanowire shrinks in size, the surface atoms become more numerous compared to the atoms within the nanowire, and edge effects become more important.

Furthermore, the conductivity can undergo a quantization in energy: i.e. the energy of the electrons going through a nanowire can assume only discrete values, multiple of the Von Klitzing constant (G) = 2e2/h (where e is the charge of the electron and h is the Planck’s constant). The conductivity is hence described as the sum of the transport by separate channels of different quantized energy levels. The thinner the wire is, the smaller the number of channels available to the transport of electrons.

The quantized conductivity is more pronounced in semiconductors like Si or GaAs than in metals, due to lower electron density and lower effective mass. Quantized conductance can be observed in 25 nm wide silicon fins, resulting in increased threshold voltage. 21

  • Applications of Nanowire

 

 

payment

SYNTHESIS AND CHARACTERIZATION OF ZEOLITE AND ITS APPLICATION IN ADSORPTION OF NICKEL FROM AQUEOUS SOLUTION

CHAPTER ONE

  • Introduction

Zeolites are porous crystalline alumino-silicates of regular skeleton structures formed by alternating silicon-oxygen and aluminum-oxygen tetrahedrons. Although only natural zeolites were initially used, synthetic zeolites, due to their well-tailored and highly-reproducible structures, have been used extensively as ion exchangers, adsorbents, separation materials and catalyst1.The negative charges in aluminum-oxygen tetrahedron, which are not rigidly fixed to the skeleton of zeolites, are compensated with cations, so they are capable of interchanging. Silicon-oxygen and aluminum-oxygen tetrahedrons in the zeolites of the type A, X and Y form a complex structural unit of cubooctahedron. The combination of such units forms the structure of type A, X and Y [fig 7].. The difference between them consists in the fact that they are interconnected by means of different number of member rings (i.e., eight member rings (A), twelve member rings (X, Y). The chemical difference of zeolite is defined by the ratio of Si/Al. For zeolite A this values is in the range of 0.95-1.051-3. Zeolites A, X and Y are the most important ones to be used in pharmaceutical, petrochemical and detergent industries.

Zeolites with different structure are known to be obtained by synthesis 2-7. They are either synthesized from alumino-silicate hydrogel or by conversion of clay minerals. The hydrogel can be prepared from different sources of silica and alumina, but the types of starting materials and the method of mixing determine the structure of the resulting gel. Moreover, the nature of the gel influences the rate of the subsequent crystallization, which affects the particle size distribution, and the formation of impurities8. The general pathway for zeolite synthesis follows a specific temperature gradient at low temperatures (<60 oC) where the sources of aluminum, silicon and water are placed in solution and mixed until a gel is formed9.

 

payment

SYNTHESIS AND CHARACTERISATION OF ALKYLATED ISOCYANATE DERIVATIVES OF [Pt2(µ-S)2(PPh3)4]

CHAPTER ONE

 Introduction

1.1      Background of Study

             Investigation of the chemistry of platinum and sulphur has attracted considerable attention in recent years due to the broad applications of the two elements and their compounds, in biological systems1, applied catalysis2,3 and to the chemistry of novel molecular systems4. Other main areas of application are in the design of homo- and hetero-polynuclear  clusters5, fine wires6,7, jewellery, antitumor drugs8, the self-assembly of supramolecular structures, and the photophysical properties of new luminescent and mesogenic phases9. Platinum, however has six naturally occurring isotopes, 190Pt, 192Pt, 194Pt, 195Pt, 196Pt and 198Pt with a maximum oxidation state of +6, the oxidation states of +2 and +4 being the most  stable10,11 and the rare odd number form of +1 and +3 oxidation states are found in dinuclear Pt-Pt bonded complexes12.

Sulphur also exhibits an important chemical properties especially as a versatile coordinating ligand which is illustrated by its ability to catenate forming polysulfide ligands (Sn2) with n ranging from 1 to 8. It also has the ability to expand its coordination from terminal groups example ([Mo2S10]2-)13, to μ-sulfido group e.g. [Pt2(l-S)2(PPh3)4]14 and to an encapsulated form e.g. [Rh17(S)2(CO)32]3-  consisting of a S-Rh-S moiety in the cavity of a rhodium-carbonyl cluster15,. The coordination chemistry of sulfur ligands has been reviewed and has shown a unique variety of structure in its reactions with most transition metals in different oxidation states16.

The outstanding ability of sulphur to bind to heavy metals is not only evidenced by the enormous variety of the metal sulfide minerals found in nature but also by the appearance of platinum group metals in mineral ores different from the naturally occurring ores17,18. examples are Cooperite (Pt0.6Pd0.3Ni0.1S)17,18, and Braggite (Pt0.38Pd0.50 Ni0.10S1.02)17.

The development of platinum sulfide complexes has received much less attention for many years after the first platinum-sulfur complex, (NH4)2[Pt(η2-S5)3], was isolated in 190319 . However the main features in the field of platinum(II)sulfur chemistry was established by Chatt and Mingos in 1970, who obtained several complexes of various nuclearities and structures20. Among them,  [Pt2(μ-S)2(PMe2Ph)4] followed by [Pt2(μ-S)2(PPh3)4]14 {bis(μ-sulfido)tetrakis (triphenylphosphine) diplatinum (II)} reported by Ugo et al14 a year later,  constitutes the first examples  of platinum(II)sulphide complexes containing the  {Pt2(μ-S)2} core21. The compound is a fine orange powder, insoluble in hydrocarbon solvents and water but sparingly soluble in methanol. It is soluble by reaction with mild alkylating agents, e.g CH2Cl2, CH3Cl which indicates the high nucleophilicity of the sulfide centres.

The exceptional nucleophilicity of the sulfido ligands in {Pt2(μ-S)2} core accounts for their ability to act as  potent metalloligands towards a diverse range of metal centres, including main group21-23and transition metals23-28, as well as the actinide uranium9 and also enhances the development of homo-, hetero- and inter-metallic sulfide complexes23 (Scheme 1.1). The advancement in the chemistry of [Pt2(μ-S)2(PPh3)4] and the other sulfide-bridged complexes with the {Pt2(μ-S)2} core, as well as the improvement made in their synthesis, structures, and reactivity have been exceptionally reviewed by Fong and Hor,  who have made important contributions to this field23. However, the overall ability of the sulfido ligands in the {Pt2(μ-S)2} core to extend their coordination mode from μ-S to μ3-S give rise to the behaviour of [Pt2(μ-S)2(PPh3)4]14  as building blocks for the synthesis of multimetallic sulfide bridged aggregates.  Scheme 1.0 shows the different formation of multimetallic aggregates23,25 . It involves the bridging of the two sulfur atoms in a molecule of [Pt2(μ-S)2(PPh3)4] by a metal fragment.

payment

SPECTROPHOTOMETRIC DETERMINATION OF PARACETAMOL USING ZIRCONIUM (IV) OXIDE AND AMMONIUM TRIOXOVANADATE (V)

 

TABLE OF CONTENTS

Title page ————————————————————————– i

Certification———————————————————————– ii

Dedication ———————————————————————— iii

Acknowledgment—————————————————————– iv

Table of Contents —————————————————————- v

List of Tables———————————————————————- vi

List of Figures——————————————————————— vii

Abstract —————————————————————————- viii

 

CHAPTER ONE

1.0 Introduction —————————————————————– 1

1.1 Ultraviolet – visible spectrophotometry (UV – visible

spectrophotometry).——————————————————– 1

1.2 Paracetamol —————————————————————— 4

1.3 The structure of paracetamol——————————————— 5

1.4 Mechanism of action of paracetamol———————————– 6

1.5 Metabolism —————————————————————— 10

1.6 Medical uses of paracetamol ——————————————— 10

1.7 Adverse effects/toxicity ————————————————— 11

1.8 Statement of the problem ———————————————— 12

1.9 Objectives of the study—————————————————– 13

CHAPTER TWO:

2.0 Literature review———————————————————— 14

2.1 A brief historical background of paracetamol———————— 14

2.2 Methods of determining paracetamol.———————————- 17

2.2.1   Chromatographic methods of determination——————— 17

2.2.2   UV-Visible spectrophotometric methods————————— 21

2.2.3   Fluorescence spectrometric methods——————————- 27

2.3   Spectrophotometric determination of the stoichiometry of

metal to ligand in a complex——————————————— 30

CHAPTER THREE

3.0 Materials and methods —————————————————- 33

3.1 Materials ——————————————————————— 33

3.1.1   Aparatus/Equipment————————————————– 33

3.2.0   Preparation of Reagents ———————————————- 33

3.2.1   Preparation of 0.1 M paracetamol———————————– 33

3.2.2   Preparation of 0.1 M Zirconium(IV) oxide, (Zirconia)———– 33

3.2.3   Preparation of 0.1 M ammonium trioxovanadate(V)———— 34

3.3.0   Absorption spectra—————————————————— 35

3.3.1   Absorption spectrum of paracetamol——————————- 35

3.3.2 Absorption spectrum of zirconium(IV) in sodium hydroxide

Medium———————————————————————- 35

3.3.3.   Absorption spectrum of mixture of paracetamol and Zr(IV)

in sodium hydroxide medium—————————————- 36

3.3.4   Absorption spectrum of vanadium(V) in

tetraoxosulphate(VI) acid medium———————————— 36

3.3.5   Absorption spectrum of mixture of paracetamol and

vanadium(V) in tetraoxosulphate(VI) acid medium————– 36

3.4.0   Determination of the stoichimetry of the reactions

between paracetamol and the oxidants—————————– 37

3.4.1 Stoichiometry of reaction between paracetamol and

zirconium(IV)————————————————————- 37

3.4.2   Stoichiometry of reaction between paracetamol and

vanadium(V)————————————————————– 37

3.5.0   Determination of optimal conditions——————————- 38

3.5.1 Effect of pH on Zr(IV)-paracetamol reaction———————— 38

3.5.2   Effect of pH on V(V)-paracetamol reaction————————- 38

3.5.3   Effect of time on the reaction of paracetamol with

zirconium(IV)————————————————————- 38

3.5.4   Effect of time on the reaction of paracetamol with V(V)——– 39

3.5.4   Effect of temperature on the reaction paracetamol with

Zirconium(IV)————————————————————- 39

3.5.6   Effect of temperature on the reaction of paracetamol

with vanadium(V) ——————————————————– 39

3.6.0    Beer’s calibration plots———————————————– 39

3.6.1   Calibration curve for paracetamol-Zr(IV) reaction————— 39

3.6.2   Calibration curve for paracetamol-V(V) reaction—————– 40

3.7.0   Quantitative assay of the drugs————————————- 40

3.7.1   Assay of paracetamol with Zirconium(IV)————————- 40

3.7.2   Assay of paracetamol with vanadium(V)————————— 41

CHAPTER FOUR

4.0   Results and discussion————————————————– 42

4.1   Absorption spectrum of paracetamol.——————————— 42

4.2   Absorption spectrum of zirconium(IV) in NaOH medium.——- 42

4.3   Absorption spectrum of a mixture of paracetamol and

zirconium(IV) in NaOH medium ————————————— 42

4.4   Absorption spectrum of vanadium(V)

in tetraoxosulphate(VI) acid medium ——————————— 47

4.5   Absorption spectrum of the product of paracetamol-V(V)

reaction in H2SO4 medium ———————————————- 47

4.6.1   Stoichiometry of reaction between paracetamol and Zr(IV)— 49

4.6.2   Stoichiometry of reaction between paracetamol and

vanadium(V)————————————————————– 50

4.7.0   Effect of pH on the reaction of paracetamol and Zr(IV)——— 51

4.7.1   Effect of pH on paracetamol-V(V) reaction————————- 52

4.7.2   Effect of time on the reaction of paracetamol with Zr(IV)—— 53

4.7.3   Effect of time in the reaction of paracetamol with

vanadium(V)————————————————————– 54

4.7.4   Effect of temperature on paracetamol-Zr(IV) reaction———– 55

4.7.5   Effect of temperature on paracetamol-vanadium(V) reaction- 56

4.8   Beer’s calibration plot for the reaction of paracetamol

with zirconium(IV)——————————————————— 57

4.8.2   Beer’s calibration plot for the reaction of paracetamol

with vanadium(V)——————————————————— 58

4.9.0   Validation of paracetamol in dosage form with zirconium(IV)-59

4.9.1   Validation of paracetamol in dosage with vanadium(V)——– 60

CHAPTER FIVE

Conclusion———————————————————————— 61

References————————————————————————- 62

 

 

LIST OF TABLES

4.6   The mole ratio of [paracetamol]/ [Zr(IV)] and absorbance. —— 49

4.7:  The mole ratio of [paracetamol]/ [V(V)] and absorbance——— 50

4.8: Effect of pH on Zr(IV)- paracetamol reaction.———————— 51

4.9: Effect of pH on V(V)-paracetamol reaction.—————————   52

4.9: Effect of pH on V(V)-paracetamol reaction.—————————   52

4.10: Effect of Time on Paracetamol-Zr(IV) reaction———————-   53

4.11: Effect of time on paracetamol – V(V) reaction———————-   54

4.12:  Effect of temperature on paracetamol-Zr(IV) reaction————   55

4.13:  Effect of temperature on paracetamol-V(V) reaction————-   56

4.14 – Beer’s calibration plot for paracetamol-Zr(IV) reaction———   57

4.15: Beer’s calibration plot for paracetamol-V(V) reaction————-   58

4.16: Analysis of paracetamol (commercial brand) ———————-   59

4.17:  Analysis of paracetamol (commercial brand)———————-   60

4.18:  Spectral characteristics and analytical data of

paracetamol with Zr(IV) and V(V)————————————- 60

FIGURES/SCHEMES

4.1   UV spectrum of paracetamol ——————————————- 44

4.2   UV spectrum of zirconium(IV) in NaOH medium —————— 45

4.3   UV spectrum of mixture of paracetamol and

zirconium(IV) NaOH medium——————————————- 46

4.4 UV spectrum of V(V) in H2SO4 medium ——————————- 47

4.5   UV spectrum of mixture of paracetamol and V(V) in

H2SO4 medium ————————————————————-  48

4.6 Absorbance Vs mole ratio for paracetamol-Zr(IV) reaction——— 49

4.7   Absorbance Vs mole ratio for paracetamol and V(V)————— 50

4.8   Abs-pH relationship for paracetamol-Zr(IV) reaction————– 51

4.9   Abs-pH relationship for paracetamol-V(V) reaction —————  52

4.10 Abs Vs time for paracetamol-Zr(IV) reaction————————- 53

4.11   Abs Vs time for paracetamol-V(V) reaction————————- 54

4.12   Effect of temperature on paracetamol-Zr(IV) reaction———— 55

4.13   Effect of temperature on paracetamol-V(V) reaction————- 56

4.14 Beer’s calibration plot for paracetamol- Zr(IV) reaction———– 57

4.15 Beer’s calibration plot for paracetamol – V(V) reaction———– 58

 

 

SCHEMES.

1.3     4-hydroxyacetanilide (paracetamol)——————————— 5

2.6a   Oxidation of paracetamol by cerium(IV)—————————- 23

2.6b   Reaction of paracetamol with KMnO4 in acidic medium——– 27

2.7a   De-acetylation of paracetamol to p-amino phenol—————- 28

2.7b  Oxidation of paracetamol to 2,2-dihydroxy -5,5-diacetyl

diamine biphenyl diamine biphenyl——————————— 29

4.3   Oxidation reaction of paracetamol by Zr(IV)————————- 43

4.5   oxidation reaction of paracetamol by V(V)————————— 48

 

ABSTRACT

           A simple and sensitive spectrophotometric method for the determination of paracetamol was explored, using zirconium(IV) and vanadium(V) oxides. The method was based on the oxidation of paracetamol by zirconium(IV) and vanadium(V) in  alkaline and acidic media respectively. The stoichiometric studies indicated a mole-ratio of 1:1 for the reactions of paracetamol with both zirconium(IV) and vanadium(V). Effects of other variables like pH, temperature and time were determined and showed that the optimum conditions for the oxidation of paracetamol by zr(IV) were pH of 9.0,  temperature of 50˚C and at 20 min yielding red- brown p-benzoquinone which absorbed at a λmax of 420 nm. Similarly, optimum conditions for the oxidation of paracetamol by V(V) were pH of 1.0, temperature of 70˚C at 8 min, and V(V) reduced to bluish-violet vanadium(II) ions which absorbed at a λmax of 600 nm. The Beer-Lambert’s law was obeyed at a concentration range of 5.0-40.0 μg/cm3 for paracetamol with both Zr(IV) and V(V) respectively; and the correlation coefficients for both oxidants were 0.997 and 0.999 respectively. The mean % recovery of paracetamol in dosage form with Zr(IV) was 99.06 %, while V(V) gave 100.17 %. Hence, the recovery studies had proved the method to be accurate, simple and precise.

CHAPTER ONE

1.0    INTRODUCTION

Spectroscopy involves the study of the absorption and emission of light and other radiations as related to wavelength of the radiation. Hence, spectroscopy is the branch of science dealing with the study of interaction between electromagnetic radiation and matter. It is the most powerful tool available for the study of atomic and molecular structures, and is used in the analysis of wide range of samples. Optical spectroscopy includes the region on electromagnetic spectrum between 100 Ǻ and 400 m. Hence, the regions of electromagnetic spectrum are thus – far (or vacuum) ultraviolet (10-200 nm), near ultraviolet (200-400 nm), visible (400 – 750 nm), near infrared (0.75 – 2.2 m), mid infrared (2.5 – 50 m), and far infra red (50 – 100 m) region.2, 3

1.1    Ultraviolet – visible spectrophotometry (UV-visible spectrophotometry).

UV – visible spectrophotometry is one of the most frequently employed techniques in pharmaceutical analysis. It involves measuring the amount of ultraviolet or visible radiations absorbed by a substance in solution.4 Instruments which measure the ratio, or function of ratio, of the intensity of two beams of light in the UV-visible region are called ultraviolet-visible spectrophotometers.4

A spectrophotometer consists of two instruments, a spectrometer and a photometer, both housed in one cabinet. The spectrometer is used to split or resolve light in bands of wavelength before it is fed to the photometer. To achieve the designed resolution, a spectrometer is specially equipped with a high resolution wavelength selector known as monochromator. This monochromator can isolate an extremely narrow bandwidth almost comparable to a single wavelength.5

In qualitative analysis, organic compounds can be identified by the use of spectrophotometer; if any recorded data is available; and quantitative spectrophotometric analysis is used to ascertain the quantity of molecular species absorbing the radiation.4

Spectrophotometric technique is simple, rapid, moderately specific and applicable to small quantities of compounds. The fundamental law that governs the quantitative spectophotometric analysis is the Beer-Lambert’s law.

Beer’s Law: it states that the intensity of a beam of parallel monochromatic radiation decreases exponentially with the number of absorbing molecules. In other words, absorbance is proportional to the concentration.

Lambert’s law: It states that the intensity of a beam of parallel monochromatic radiation decreases exponentially as it passes through a medium of homogeneous thickness. A combination of these two laws yields the Beer – Lambert law.4

Beer – Lambert’s Law: When a beam of light is passed through a transparent cell containing a solution of an absorbing substance, reduction of the intensity of light may occur. Mathematically, Beer – Lambert’s law is expressed as –

payment

SPECTROPHOTOMETRIC DETERMINATION OF NIACIN, THIAMINE, GLIBENCLAMIDE, ERYTHROMYCIN AND PARA AMINO BENZO IC ACID USING 2, 3 – DICHLORO – 5, 6 – DICYANO – 1, 4 – BENZOQUINONE

ABSTRACT
A simple and sensitive spectrophotometric method is described for the assay of the drugs; niacin, glibenclamide, erythromycin, thiamine and 4-aminobenzoic acid. The method is based on charge transfer complexation (CT) reaction of niacin, glibenclamide, erythromycin, thiamine and 4-aminobenzoic acid as n-electron donors with 2,3-dichloro-5,6-dicyno-1,4-benzoquinone(DDQ) as л-electron acceptor in methanol. Intensely coloured charge transfer complexes with niacin (reddish brown, max ;464 nm; εmax, 1.02×103 dm3mol-1cm-1) thiamine (reddish brown ,max ;474 nm; εmax, 1.08×103 dm3mol-1cm-1), glibenclamide (reddish brown , max ;474 nm; εmax,0.99×103 dm3mol-1cm-1) erythromycin(reddish brown , max ;464 nm; εmax, 1.27×103 dm3mol-1cm-1) 4-aminobenzoic acid(reddish brown, max ;474nm; εmax, 1.06×103 dm3mol-1cm-1) all in a 1:1 stoichiometric ratio. Condition for complete reactions and optimum stability of complexes were niacin (70 min, 60 OC) thiamine (25 min, 40 OC), glibenclamide (35 min, 40 OC), erythromycin (15 min, 60 OC) and 4-aminobenzoic acid (15 min, 60 OC) as absorbances of the complexes remained invariant within these conditions. Formation and stability of the complexes of niacin, thiamine, 4-aminobenzoic acid and erythromycin were optimum at pH 8. For glibenclamide pH 2.0 favoured optimum stability and formation. The bands distinguished for the donors to donor-acceptor CT complexes displayed small changes in band intensities and frequency values in the IR spectra ,The –NH2 group vibration occurring at 3609 cm-1 shifted to 3610 cm-1 in thiamine, PABA (3222 cm-1 to 3183 cm-1), ѵ (N-H) occurring at 3331cm-1 shifted to 3371 cm-1 in glibenclamide, ѵ(C=N) occurring at 2936 cm-1 shifted to 2944 cm-1 in niacin, ѵ (CH3-N) occurring at 2948 cm-1 shifted to 2939 cm-1 in erythromycin. The vibration ѵ (C= O) of DDQ observed at 1665 cm-1 shifted to 1669 cm-1 in the CT complex for thiamine, PABA(1665 cm-1 to 1670 cm-1), glibenclamide(1675 cm-1 to 1676 cm-1), erythromycin(1665 cm-1 to 1674 cm-1), niacin(1665 cm-1 to 1655 cm-1) respectively. Adherence to Beer’s Law was within the concentration range for niacin (5-130 μg/cm3), thiamine (5-80 μg/cm3), glibenclamide (9-100 µg/cm3), erythromycin
(5-150 µg/cm3), 4-aminobenzoic acid(5-90 µg/cm3). Limit of detection and quantification of the drugs based on this method is niacin (1.78 and 5.4), thiamine (1.23 and 3.37), glibenclamide (3.47 and 10.5), erythromycin (2.11 and 6.40), 4-aminobenzoic acid (0.55 and 1.67) respectively. Evaluation of the degree of interference by excipients used in the drugs manufactured indicates tolerance to certain concentrations. A detailed study on the interference of different excipients was made. No significant interference was observed in magnesium stearate (30 µg/cm3), Talc (15-25µg/cm3, 35-40 µg/cm3) with thiamine-DDQ complex. There were no significant interference in stearic acid (35 µg/cm3) but tolerable interference was seen in magnesium stearate (20 µg/cm3) and calcium phosphate (15 µg/cm3) with niacin-DDQ complex. For glibenclamide – DDQ complex, no significant interference was seen with calcium phosphate (30 µg/cm3) but there were tolerable interference present in stearic acid (40 µg/cm3). In 4-aminobenzoic acid, no significant interference was observed with magnesium stearate (30 µg/cm3) and talc (35 -40µg/cm3) but tolerable interference was observed in corn starch (15 µg/cm3). Also no significant interference was seen in corn starch (35 µg/cm3) with erythromycin-DDQ complex but there was tolerable interference in talc (10 µg/cm3). The Pearson correlation coefficient for the compliance of the method as regards the pure and commercial forms of niacin, thiamine, glibenclamide, erythromycin and 4-aminobenzoic acids are 0.993, 0.977, 0.987, 0.998 and 0.993 respectively which shows significance with p < 0.01. The analysis of variance test revealed the non-significance of niacin, thiamine, glibenclamide, erythromycin and 4-aminobenzoic acid with p > 0.01. The mean percentage recoveries were 98.94 ± 0.016, 96.2 ± 0.016, 98.24 ± 0.011, 107.4 ± 0.023 and 102.35 ± 0.014 for niacin, thiamine, glibenclamide, erythromycin and 4-aminobenzoic acid respectively. Kinetics of the reactions infer that the rate of formation of the CT complexes did not vary significantly with increase in concentration of glibenclamide, erythromycin, thiamine, niacin and 4-aminobenzoic acid indicating likely zeroth order dependence of the rate with respect to concentration of the drugs. However, the linearity of the pseudo-first order plot points to first order dependence of rate on [DDQ].The overall rate equation for the reactions can be given as

-(d[DDQ])/dt=k_(obs ) [DDQ]

Based on the limit of detection and quantification, adherence to Beer-Lambert’s law and low degree of interference, the method is recommended for the analysis of these drugs.

TABLE OF CONTENTS

Title page – – – – – – – – – – i
Declaration – – – – – – – – – – ii
Certification page – – – – – – – – iii
Dedication – – – – – – – – – iv
Acknowledgement – – – – – – – – v
Abstract – – – – – – – – – iv
Table of Contents – – – – – – – – ix
List of Figures – – – – – – – – – xxii
List of Tables – – – – – – – – – xxvii
Abbreviations- – – – – – – – – – xxxiv
Chapter One
1.0 Introduction – – – – – – – 1
1.1 Charge transfer complexation- – – – – – 1
1.1.2 Analysis of Drugs – – – – – – 2
1.1.3 Justification of the study – – – – – – 6
1.1.4 Problem of the study – – – – – – – 6
1.1.5 Aims and Objectives- – – – – – – – 7
1.1.6 Scope of study- – – – – – – – 8
Chapter Two
2.0 Literature Review – – – – – – – 9
2.1 Charge transfer complex – – – – – 9
2.1.1 Marcus theory- – – – – – – – – 11
2.1.2 The one electron redox reaction – – – – – 11
2.1.3 The outer sphere electron transfer- – – – – – 12
2.2 Charge transfer transition energy – – – – – 13
2.3 Identification of CT bands – – – – – – 13
2.4 Spectroscopy – – – – – – – – 14
2.4.1 Different spectroscopic techniques – – – – – 14
2.4.2 Spectrophotometry – – – – – – 15
2.4.3 Major classes of spectrophotometer – – – – – 16
2.4.4 Terms used in U.V spectroscopy – – – – – 16
2.5 Absorption laws – – – – – – – 17
2.6 2,3- dichloro-5,6- dicyano-1, 4- benzoquinone – – – 18
2.6.1 Previous studies on DDQ- – – – – – – 20
2.7 Niacin (Pyridine – 3 – Carboxylic acid) – – – – 20
2.7.1 Previous studies on niacin – – – – – 21
2.8 Vitamin B1 (Thiamine Hydrochloride) – – – 22
2.8.1 Previous studies on thiamine hydrochloride- – – – 23
2.9 Glibenclamide – – – – – – – – 24
2.9.1 Previous studies on glibenclamide – – – – – 25
2.10 Erythromycin – – – – – – – – 26
2.10.1 Previous studies on erythromycin – — – – – 26
2.11 Para Aminobenzoic acid (PABA) – – – – – 28
2.11.1 Previous studies on PABA — – – – – – 28

Chapter Three
3.0 Experimental – – – – – – – – 30
3.1 Materials and Methods – – – – – – 30
3.1.1 Drugs used and their sources – – – – – – 30
3.2 Preparation of reagents and standard solutions – – – 32
3.2.1 Preparation of 2, 3-dichloro-5, 6- dicyano 1,
4- benzoquinone – – – – – – – 32
3.2.2 Preparation of Standard solution of erythromycin – – – 32
3.2.3 Preparation of standard solution of glibenclamide – – – 32
3.2.4 Preparation of Standard solution of niacin – – – 32
3.2.5 Preparation of standard solutions of paraminobenzoic acid (PABA) – – – – – – – – 33
3.2.6 Preparation of standard solutions of thiamine
hydrochloride – – – – – – – 33
3.3 Absorption spectra – – – – – – – – 33
3.3.1. Absorption spectra of 2,3- dichloro -5,6- dicyano -1,
4-benzoquinone – – – – – – – 33
3.3.2. Absorption spectra of erythromycin – – – – 33
3.3.3 Absorption spectra of glibenclamide – – – – 34
3.3.4 Absorption spectra of thiamine hydrochloride – – – 34
3.3.5 Absorption spectra of niacin – – – – – – 34
3.3.6 Absorption spectra of paraminobenzoic acid – – – 34
3.4.1 Absorption spectra of erythromycin-DDQ complex – – – 34
3.4.2 Absorption spectra of glibenclamide-DDQ complex – – – 34
3.4.3 Absorption spectra of thiamine hydrochloride-DDQ
Complex – – – – – – — – 35
3.4.4 Absorption spectra of niacin-DDQ complex – – – 35
3.4.5 Absorption spectra of paraminobenzoic acid–DDQ
Complex – – – – – – – – 35
3.5 Stoichiometry of complexes – – – – – – 35
3.5.1 Stoichiometry of Erythromycin–DDQ Reaction – – – 35
3.5.2 Stoichiometry of Glibenclamide – DDQ Reaction – – – 36
3.5.3 Stoichiometry of Thiamine Hydrochloride – DDQ Reaction – – 36
3.5.4 Stoichiometry of Niacin-DDQ Reaction – – – – 36
3.5.5 Stoichiometry of PABA- DDQ Reaction – – – – 37
3.6 Effect of time on the formations of complexes- – – – 37
3.6.1 Effect of time on the formations of erythromycin–DDQ complex – 37
3.6.2 Effect of time on the formation of glibenclamide-DDQ complex – 37
3.6.3 Effect of time on the formation of thiamine
hydrochloride-DDQ complex – – – – – 38
3.6.4 Effect of time on the formation of PABA- DDQ Complex – – 38
3.6.5 Effect of time on the formation of niacin- DDQ complex — – 38
3.7 Effect of solvents on formation of complexes- – – – 38
3.7.1 Effect of solvents on erythromycin -DDQ complex – – – 38
3.7.2 Effect of solvents on glibenclamide – DDQ complex – – 39
3.7.3 Effect of solvents on complex formation of thiamine hydrochloride – 39
3.7.4 Effect of solvents on niacin – DDQ complex – – – – 39
3.7.5 Effect of solvents on PABA- DDQ complex – – – – 40
3.8 Effect of temperature on formation complexes – – – 40
3.8.1 Effect of temperature on erythromycin-DDQ complex – – 40
3.8.2 Effect of temperature on glibenclamide-DDQ complex – – 40
3.8.3 Effect of temperature on thiamine- DDQ complex – – 40
3.8.4 Effect of temperature on niacin- DDQ complex – – – 41
3.8.5 Effect of temperature on PABA- DDQ complex – – – 41
3.9 pH study on formation of complexes – – – – – 41
3.9.1 pH study on erythromycin –DDQ complex – – – 41
3.9.3 pH study on glibenclamide-DDQ complex – – – – 41
3.9.4 pH study on thiamine hydrochloride-DDQ complex – – 41
3.9.5 pH study on niacin- DDQ complex – – — – – 42
3.9.6 pH study on PABA-DDQ complex – – — – – 42
3.10 Determination of association constant, molar absorptivity,
Free energy and Benesi- Hildebrand plot of the complexes- – 42
3.10.1 Benesi–Hildebrand plot of erythromycin-DDQ complex – – 42
3.10.2 Benesi- Hildebrand plot of glibenclamide- DDQ complex – – 42
3.10.3 Benesi – Hildebrand plot of thiamine hydrochloride-
DDQ complex – – – – – — – – 43
3.10.4 Benesi – Hildebrand plot of niacin –DDQ complex – – 43
3.10.5 Benesi-Hildebrand plot of PABA-DDQ complex – – – 44
3.2 Beer’s calibration plot for the formation of complexes – – 44
3.21 Beer’s calibration plot of erythromycin –DDQ complex – – 44
3.22 Beer’s calibration plot of glibenclamide –DDQ complex- – – 44
3.23 Beer’s calibration plot of PABA –DDQ complex – – – 45
3.24 Beer’s calibration plot of niacin-DDQ complex – – – 45
3.25 Beer’s calibration plot of thiamine–DDQ complex – – – 45
3.30 Interference studies on complex formation – – – – 46
3.31 Interference studies of erythromycin-DDQ complex – – – 46
3.32 Interference studies of thiamine hydrochloride-DDQ Complex – 46
3.33 Interference studies of niacin –DDQ complex – – – 46
3.34 Interference studies of PABA-DDQ complex – – – 47
3.35 Interference studies of glibenclamide-DDQ complex – – 47
3.40 Assay of dosage forms of drug samples – – – – – 47
3.41 Assay of dosage form of erythromycin drug – – – – 48
3.42 Assay of dosage form of glibenclamide drug – – – – 48
3.43 Assay of dosage form of thiamine drug- – – – – 48
3.44 Assay of dosage form of niacin drug – – – – 49
3.45 Assay of dosage form of PABA drug – – – – – 49
3.5 Kinetic measurements – – – – – – – 50
Chapter Four
4.1.1 Results – – – – – – – – – 52
4.1.2 Absorption spectra of the complex – – – – – 52
4.20 Stoichiometric relationship of erythromycin-DDQ Complex – – 81
4.21 Stoichiometric relation of glibenclamide –DDQ complex – – 81
4.22 Stoichiometric relationship of thiamine hydrochloride-DDQ complex – 81
4.23 Stoichiometric relationship of niacin-DDQ complex – – – 81
4.24 Stoichiometric relationship of PABA- DDQ complex- – – 81
4.30 Effect of time on the formation of complex – – – – 95
4.31 Maximum time for the formation of erythromycin-DDQ Complex – 95
4.32 Effects of time on glibenclamide-DDQ complex – – – 95
4.33 Effect of time on thiamine-DDQ complex – — – – 95
4.34 Effects of time on niacin-DDQ complex – — – – 95
4.35 Effects of time on PABA- DDQ complex – — – – 95
4.40 Effect of temperature on complexation- – – – – 108
4.41 Effect of temperature on the erythromycin-DDQ Complex – – 108
4.42 Effect of temperature on glibenclamide-DDQ Complex – – 108
4.43 Effects of temperature on thiamine hydrochloride-DDQ complex – 108
4.44 Effects of temperature on niacin-DDQ complex – – – 108
4.45 Effect of temperature on PABA- DDQ complex- – – – 109
4.50 pH studies of the complexes – – — – – – 120
4.51 pH study of erythromycin-DDQ complex — – – – 120
4.52 pH study of glibenclamide -DDQ complex – – – – 120
4.53 pH study of thiamine hydrochloride-DDQ complex – – – 120
4.54 pH study of niacin-DDQ complex – – – – – 120
4.55 pH study of PABA-DDQ complex – – – – – 120
4.6 Association constant, molar absorptivity, free gibb’s
energy, enthalpy and entropy changes of the complexes – – 131
4.6.1 Association constant, molar absorptivity, free energy,
enthalpy and entropy changes of the erythromycin-DDQ complex – 131
4.6.2 Association constant, molar absorptivity, free energy,
enthalpy and entropy changes of the glibenclamide-DDQ complex – 142
4.6.3 Association constant, molar absorptivity, free energy,
enthalpy and entropy changes of the thiamine- DDQ complex – 152
4.6.4 Association constant, molar absorptivity, free energy,
enthalpy and entropy changes of the niacin- DDQ complex – 162
4.6.5 Association constant, molar absorptivity, free energy,
enthalpy and entropy changes of the PABA- DDQ complex – – 172
4.7 Beer’s calibration plots of the complexes – – 182
4.7.1 Beer’s calibration plot for erythromycin-DDQ Complex – – 182
4.7.2 Beer’s calibration plot for glibenclamide – – – – 184
4.7.3 Beer’s calibration plot of thiamine –DDQ complex – – – 186
4.7.4 Beer’s calibration plot for niacin-DDQ complex – – 188
4.7.5 Beer’s calibration plot for PABA-DDQ complex – – – 190
4.8.1 Recovery experiment of erythromycin-DDQ complex – – 192
4.8.2 Recovery experiment of glibenclamide-DDQ complex – – 195
4.8.3 Recovery experiment of thiamine-DDQ complex – – – 197
4.8.4 Recovery experiment of niacin-DDQ complex – – – – 199
4.8.5 Recovery experiment of PABA-DDQ complex – – – 201
4.9.1 Pharmaceutical interference studies on thiamine–DDQ complex – 203
4.9.2 Pharmaceutical interference studies on niacin –DDQ complex – 204
4.9.3 Pharmaceutical interference studies on glibenclamide–DDQ complex – 205
4.9.4 Pharmaceutical interference studies on PABA–DDQ Complex – 206
4.9.5 Pharmaceutical interference studies on erythromycin-DDQ complex 207
4.10 Determination of order of reactions – – – – – 208
4.10.1 Reaction of glibenclamide with DDQ – – – – 208
4.10.2 Reaction of erythromycin with DDQ – – – – – 211
4.10.3 Reaction of niacin with DDQ – – – – – 213
4.10.4 Reaction of PABA with DDQ – – – – – 216
4.10.5 Reaction of thiamine with DDQ – – – – – 219
4.10.6 Effect of temperatures on reaction rate of erythromycin-DDQ complex 222
4.10.7 Effect of temperatures on reaction rate of glibenclamide-DDQ complex 227
4.10.8 Effect of temperatures on reaction rate of niacin-DDQ Complex – 232
4.10.9 Effect of temperatures on reaction rate of PABA-DDQ Complex – 237
4.10.10 Effect of temperatures on reaction rate of thiamine-DDQ Complex 242
4.10.11 Effect of pH1-pH13 on reaction rate of erythromycin-DDQ Complex 248
4.10.12 Effect of pH1-pH13 on reaction rate of glibenclamide-DDQ complex 250
4.10.13 Effect of pH1-pH13 on reaction rate of niacin-DDQ complex – 252
4.10.14 Effect of pH1-pH13 on reaction rate of PABA-DDQ complex – 254
4.10.15 Effect of pH1-pH13 on reaction rate of thiamine – DDQ complex – 256
4.10.16 Effect of hydrogen ion concentration on reaction rate of – – 258
4.10.17 Effect of hydrogen ion concentration on reaction rate of PABA complex- 260
4.10.18 Effect of hydrogen ion concentration on reaction rate of niacin complex – 262
10.19 Effect of hydrogen ion concentration on reaction rate of
thiamine complex – – – – – – – – 264
4.10.20 Effect of hydrogen ion concentration on reaction rate of
erythromycin complex– – – – – – – 266
4.10.21 Effect of ionic strength on erythromycin-DDQ Complex – 268
4.10.22 Effect of ionic strength glibenclamide-DDQ Complex- – – 270
4.10.23 Effect of ionic strength on niacin-DDQ Complex- – – — 272
4.10.24 Effect of ionic strength on PABA-DDQ Complex- – – 274
4.10.25 Effect of ionic strength on thiamine-DDQ Complex- – – 276
4.10.26 Rate determining Steps of drugs-DDQ complex – – – 278
4.10.27 Infrared frequencies and tentative assignments for drugs and reagent – 282
Chapter Five
5.0 .1 Discussion- – – – – – – – 287
5.0.2 Absorption Spectra- – – – – – – – 287
5.0.3 Absorption spectra of erythromycin complex- – – – 288
5.0.4 Absorption spectra of erythromycin in different solvent- – – 299
5.0.5 Absorption spectra of glibenclamide complex- – – – 290
5.0.6 Absorption spectra of glibenclamide in different solvent – – 291
5.0.7 Absorption spectra of thiamine complex- – – – – 292
5.0.8 Absorption spectra of thiamine in different solvent- – – – 293
5.0.9 Absorption spectra of niacin complex- – – – – 293
5.0.10 Absorption spectra of niacin in different solvent- – – – 294
5.0.11 Absorption spectra of PABA complex- – – – 294
5.0.12 Absorption spectra of PABA in different solvent- – – – 295
5.1 Stoichiometric relationship of erythromycin-DDQ Complex – – 296
5.1.1 Stoichiometric relation of glibenclamide –DDQ complex – – 296
5.1.2 Stoichiometric relationship of thiamine hydrochloride-DDQ complex 296
5.1.3 Stoichiometric relationship of niacin-DDQ complex — – – 297
5.1.4 Stoichiometric relationship of PABA- DDQ complex – – 297
5.2 Effect of time on the formation of complex – – – – 297 5.2.1 Maximum time for the formation of erythromycin-DDQ Complex – 297
5.2.2 Effects of time on glibenclamide-DDQ complex – – – 297
5.2.3 Effect of time on thiamine-DDQ complex – – – – 298
5.2.4 Effects of time on niacin-DDQ complex – – – – 298
5.2.5 Effects of time on PABA- DDQ complex – – – – 298
5.3 Effect of temperature on complexation – – – – 298
5.3.1 Effect of temperature on the erythromycin-DDQ Complex – – 298
5.3.2 Effect of temperature on glibenclamide-DDQ Complex- – – 299
5.3.3 Effects of temperature on thiamine hydrochloride- DDQ complex – 299
5.3.4 Effects of temperature on niacin-DDQ complex – – – 300
5.3.5 Effect of temperature on PABA- DDQ complex – – – 300
5.4 pH studies of the complexes – – – – – – 301
5.4.1 pH study of erythromycin-DDQ complex – – – – 301
5.4.2 pH study of glibenclamide -DDQ complex – – – – 301
5.4.3 pH study of thiamine hydrochloride-DDQ complex – – – 301
5.4.4 pH study of niacin-DDQ complex – – – – – 301
5.4.5 Effect of pH medium on the formation of PABA-DDQ complex – 302
5.5 Association constant, molar absorptivity, free Gibb’s energy, enthalpy
and entropy changes for the formation of the complexes – – 302
5.5.1 Association constant, molar absorptivity, free energy,
enthalpy and entropy changes of the erythromycin-DDQ complex – 302
5.5.2 Association constant, molar absorptivity, free energy,
enthalpy and entropy changes of the glibenclamide-DDQ complex – 303
5.5.3 Association constant, molar absorptivity, free energy,
enthalpy and entropy changes of the thiamine- DDQ complex – 304
5.5.4 Association constant, molar absorptivity, free energy,
enthalpy and entropy changes of the niacin- DDQ complex – 305
5.5.5 Association constant, molar absorptivity, free energy, enthalpy and
entropy changes of the PABA- DDQ complex – – – 305
5.6 Beer’s calibration plots for the formation of the complexes – – 306
5.6.1 Beer’s calibration plot for the formation of erythromycin – DDQ complex – 306
5.6.2 Beer’s calibration plot for the formation of glibenclamide-DDQ complex – 306
5.6.3 Beer’s calibration plot for the formation of thiamine – DDQ complex – 306
5.6.4 Beer’s calibration plot for the formation of niacin – DDQ complex – 307
5.6.5 Beer’s calibration plot for the formation of PABA – DDQ complex – 307
5.7.1 Recovery studies on the formation of erythromycin-DDQ reaction – 307
5.7.2 Recovery studies on the formation of glibenclamide-DDQ reaction – 307
5.7.3 Recovery studies on the formation of thiamine-DDQ reaction – 308
5.7.4 Recovery studies on the formation of niacin-DDQ reaction – – 308
5.7.5 Recovery studies on the formation of PABA-DDQ reaction – – 308
5.8.1 Interference studies on the formation of thiamine–DDQ complex – 308
5.8.2 Interference studies on the formation of niacin – DDQ complex – 309
5.8.3 Interference studies on the formation of PABA –DDQ complex 311
5.8.4 Interference studies on the formation of PABA –DDQ complex – 313
5.8.5 Interference studies on the formation of erythromycin -DDQ complex 313
5.8.6 Kinetics measurement – – – – – – 315
5.8.7 Determination of order of reactions – – – – – 315
5.8.8 Determination of order of reactions – – – – – 317
5.8.9 Determination of order of reactions – – – – – 318
5.8.10 Determination of order of reactions – – – – – 320
5.8.11 Determination of order of reactions – – – – – 321
5.8.12 FTIR characterization of the complexes – – – – 322
Chapter Six
6.0. Conclusion and Recommendation- – – – – – 323
References – – – – – – – – – 326
Appendix – – – – – – – – – – 339

LIST OF FIGURES
2.0 2,3-dichloro-5,6- dicyano -1,4 – benzoquinone – – – – 18
2.1 Structure of nicotinic acid- – – – – – – 20
2.2 Structure of thiamine- – – – – – – – 22
2.3 Structure of glibenclamide- – – – – – – 24
2.4 Structure of erythromycin- – – — – – 26
2.5 Structure of PABA- – – – – – – – 28
4.1 Absorption spectra of DDQ in methanol medium – – 54
4.2 Absorption spectra of erythromycin in methanol – – 55
4.3 Absorption spectra of thiamine in methanol – – – 56
4.4 Absorption spectra of glibenclamide in methanol – – 57
4.5 Absorption spectra of niacin in methanol – – – – 58
4.6 Absorption spectra of PABA in methanol medium – – 59
4.7 Absorption of spectra of erythromycin–DDQ complex – – 61
4.8 Absorption of spectra of erythromycin in
ethanol-DDQ in methanol – – – – 62
4.9 Absorption of spectra of erythromycin in
chloromethane- DDQ in methanol complex – – – – 63
4.10 Absorption of spectra of erythromycin in ethylacetate-
DDQ in methanol complex. – – – – – – 64
4.11 Absorption spectra of glibenclamide in methanol –DDQ
in methanol complex – – – – – – – 65
4.12 Absorption spectra of glibenclamide in ethanol –DDQ
in methanol complex – – – – – – – 66
4.13 Absorption spectra of glibenclamide in chloromethane-DDQ
in methanol complex – – – – – – – 67
4.14 Absorption spectra of glibenclamide in ethylacetate–
DDQ in methanol complex – – – – – – 68
4.15 Absorption spectra of thiamine hydrochloride in methanol–
DDQ in methanol complex – – – – – – 69
4.16 Absorption spectra of thiamine hydrochloride in ethanol–
DDQ in methanol complex – – – – – – 70
4.17 Absorption spectra of thiamine hydrochloride
chloromethane –DDQ in methanol complex – – – – 71
4.18 Absorption spectra of thiamine hydrochloride in
ethylacetate-DDQ in the methanol. – – – – – 72
4.19 Absorption spectra of niacin in methanol–DDQ methanol – – 73
4.20 Absorption spectra of niacin in ethanol –DDQ in methanol complex – 74
4.21 Absorption spectra of niacin in chloromethane –DDQ in complex – 75
4.22 Absorption spectra of niacin in ethylacetate –DDQ methanol complex- 76
4.23 Absorption spectra of PABA in methanol medium – – – 77
4.24 Absorption spectra of PABA in ethanol-DDQ in methanol Medium 78
4.25 Absorption spectra of PABA in chloromethane-DDQ in methanol – 79
4.26 Absorption spectra of PABA in ethylacetate-DDQ in Methanol – 80
4.27 Job’s plot of erythromycin- DDQ complex – – – – 82
4.28 Stoichiometric ratio of glibenclamide –DDQ complex – – 85
4.29 Stoichiometric ratio of thiamine hydrochloride-DDQ Complex – 88
4.30 Stoichiometric ratio of niacin-DDQ complex – – – – 91
4.31 Stoichiometric relationship of PABA –DDQ complex – – 94
4.32 Time of complex formation of erythromycin-DDQ Complex – 98
4.33 Glibenclamide-DDQ complex – – – – – 100
4.34 Effect of time on thiamine complex – – – – – 102
4.35 Effects of time on niacin-DDQ complex – – – – 104
4.36 Effects of time on PABA-DDQ complex – – – – 106
4.37 Effects of temperature on erythromycin-DDQ complex – – 110
4.38 Effects of temperature on glibenclamide-DDQ complex – – 112
4.39 Effects of temperature on thiamine hydrochloride-DDQ Complex – 114
4.40 Effects of temperature on niacin-DDQ complex – – – 116
4.41 Effects of temperature on DDQ complex – – – – 118
4.42 Effects ph study of erythromycin- DC complex – – – 121
4.43 Study of glibenclamide-DDQ complex – – – – 123
4.44 pH study of thiamine hydrochloride-DDQ complex – – 125
4.45 pH study of PABA-DDQ complex – – – – – 127
4.46 Effect of pH on formation of PABA-DDQ complex – – – 129
4.47 Benesi plot of erythromycin-DDQ complex – – – – 132
4.48 Benesi plot for the formation of erythromycin-DDQ complex – – 133
4.49 Benesi plot for the formation of erythromycin-DDQ complex- – 134
4.50 Benesi plot for the formation of erythromycin-DDQ complex – – 135
4.51 Log k plot of erythromycin-DDQ complex – – – – 140
4.52 Benesi plot of glibenclamide – – – – – – 143
4.56 Log k plot of glibenclamide-DDQ complex – – – – 150
4.57 Benesi plot of thiamine-DDQ complex – – – 153
4.61 Log k plot of thiamine-DDQ complex- – – – – 160
4.62 Benesi plot of niacin-DDQ complex – – – – – 163
4.66 Log k of plot niacin-DDQ complex – – – – – 170
4.67 Benesi plot of PABA-DDQ complex – – – – – 173
4.71 Log k of PABA-DDQ complex – — – – – – 180
4.72 Beer’s plot of erythromycin-DDQ complex — – – – 182
4.73 Beer’s plot of glibenclamide-DDQ complex- – – – – 184
4.74 Beer’s plot of thiamine-DDQ complex- – – – – 186
4.75 Beer’s plot of niacin-DDQ complex- – – – – – 188
4.76 Beer’s plot of PABA-DDQ complex- – – – – – 190
4.77 Pseudo-first order plot of glibenclamide-DDQ reaction – – 209
4.83 Pseudo-first order plot of erythromycin –DDQ reaction – – 211
4.89 Pseudo-first order plot of niacin-DDQ reaction – – – – 214
4.95 Pseudo-first order plot of PABA-DDQ reaction – – – – 217
4.96 Pseudo-first order plot of thiamine-DDQ reaction – – – 220
4.97 Plot of log A∞-At for the formation of erythromycin-DDQ complex – 222
4.101 Plot of log A∞-At for the formation of glibenclamide-DDQ complex – 227
4.105 Plot of log A∞-At for the formation of complex niacin-DDQ complex – 232
4.109 Plot of log A∞-At for the formation of PABA-DDQ complex – – 237
4.113 Plot of log A∞-At for the formation of thiamine-DDQ complex – – 242
4.118 Representative plot of the effect of pH on erythromycin-DDQ reaction – 248
4.119 Representative plot of the effect of pH on glibenclamide-DDQ complex- 250
4.120 Representative plot of the effect of pH on niacin-DDQ complex- – 252
4.121 Representative plot of the effect of pH on PABA-DDQ complex- – 254
4.122 Representative plot of the effect of pH on thiamine-DDQ complex- – 256
4.123 Representative plot of the effect of HClO4 on the rate
glibenclamide-DDQ complex- – – – – 258
4.125 Representative plot of the effect of HClO4 on the rate PABA-DDQ
Complex- – – – – – – – – 260
4.126 Representative plot of the effect of HClO4 on the rate niacin-DDQ
complex – – – – – – – – 262
4.127 Representative plot of the effect of HClO4 on the rate thiamine-DDQ
complex- – – – – – – – – 264
4.128 Representative plot of the effect of HClO4 on the rate
erythromycin-DDQ complex- – – – – – – 266
4.129 Representative plot of the effect of ionic strength on the rate on
erythromycin DDQ complex- – – – – – – 268
4.130 Representative plot of the effect of ionic strength on the rate on
glibenclamide-DDQ complex- – – – – 270
4.131 Representative plot of the effect of ionic strength on the rate on
niacin-DDQ complex- – – – – – 272
4.132 Representative plot of the effect of ionic strength on the rate on
PABA-DDQ complex- – – — – – 274
4.133 Representative plot of the effect of ionic strength on the rate on
thiamine-DDQ complex- – – – – – 276

LIST OF TABLES
3.1.1 Equipments, their brand and uses – – – – – – 31
4.1 The molar absorptivity of drugs with DDQ reagent in different solvent – 60
4.2 Absorbances of reaction mixtures for erythromycin-DDQ system – 83
4.3 Absorbance of reaction mixtures for glibenclamide-DDQ system – – 86
4.4 Absorbance of reaction mixtures for thiamine-DDQ system – 89
4.5 Absorbance of reaction mixtures for niacin-DDQ system – – 93
4.6 Absorbance of reaction mixtures for PABA-DDQ system – – 95
4.7 Effect of time on formation of erythromycin –DDQ complex – – 99
4.8 Effect of time on formation of glibenclamide – DDQ complex – 101
4.9 Effect of time on formation of thiamine – DDQ complex – – 103
4.10 Effect of time on the formation of niacin –DDQ complex – – 105
4.11 Effect of time on the formation of PABA–DDQ complex – – 107
4.12 Temperature-Absorbance relationship for the formation of
erythromycin – DDQ complex – – – – – 111
4.13 Temperature-Absorbance relationship for the formation of
glibenclamide -DDQ complex – – – – – 113
4.14 Temperature-Absorbance relationship for the formation of
thiamine- DDQ complex – – – – – – 115
4.15 Temperature-Absorbance relationship for the formation of
niacin-DDQ complex – – – – – – 117
4.16 Temperature-Absorbance relationship for the formation of
PABA DDQ complex – – – – – – 119
4.17 Effect of pH on formation of erythromycin-DDQ complex – – 122
4.18 Effect of pH on formation of glibenclamide – DDQ complex – – 124
4.19 Effect of pH on formation of thiamine -DDQ complex – – 126
4.20 Effect of pH on formation of niacin -DDQ complex – – – 128
4.21 Effect of pH on formation of PABA -DDQ complex – – 130
4.23a Benesi- Hildebrand values for the formation of
Erythromycin–DDQ Complex – – – – – 137
4.23b Benesi- Hildebrand values for the formation erythromycin –
DDQ complex – – – – – – – 138
4.24 Association constant, molar absorptivity, free energy, enthalpy and
entropy changes for the formation of the erythromycin-DDQ complex – 141
4.25a Benesi-Hildebrand values for the formation of glibenclamide –
DDQ complex – – – – – – – 147
4.25b Benesi- Hildebrand values for the formation of
glibenclamide – DDQ complex – – – – – – 148
4.27 Association constant, molar absorptivity, free energy, enthalpy and
entropy changes for the formation of the glibenclamide-DDQ complex – 151
4.28a Benesi- Hildebrand values for the formation of thiamine-DDQ
Complex – – – – – – – – – 157
4.30 Association constant, molar absorptivity, free energy, enthalpy and entropy changes for the formation of the thiamine-DDQ complex – – 161
4.31 Benesi-Hildebrand values for the formation of niacin –DDQ complex – 167
4.32 Benesi-Hildebrand values for the formation of niacin –DDQ complex – 168

4.33 Association constant, molar absorptivity, free energy, enthalpy and entropy changes for the formation of the niacin-DDQ complex – – 171
4.34 Benesi – Hildebrand values for the formation of PABA –DDQ
Complex – – – – – – – – 177
4.35 Benesi – Hildebrand values for the formation of PABA –DDQ complex – 178
4.36 Association constant, molar absorptivity, free energy, enthalpy and entropy changes for the formation of the PABA-DDQ complex – – 181
4.37 Absorbance-concentration values for the formation of
erythromycin- DDQ reaction – – – – – 183
4.38 Absorbance-concentration values for the formation of
glibenclamide – DDQ complex – – – – – – 185
4.39 Absorbance-concentration values for the formation of thiamine
DDQ reaction – – – – – – – 187
4.40 Absorbance-concentration values for the formation of
niacin-DDQ reaction – – – – – – – 189
4.41 Absorbance-concentration values for the formation of
PABA-DDQ reaction – – – – – – – 191
4.42 Results of recovery studies from erythromycin-DDQ reaction – 193
4.43 Results of recovery studies from glibenclamide-DDQ reaction – 195
4.44 Results of recovery studies from thiamine-DDQ reaction – – 197
4.45 Results of recovery studies from niacin-DDQ reaction – – 199
4.46 Results of recovery studies from PABA-DDQ reaction – – 201
4.47 Pharmaceutical excipients used in the formulation of thiamine drug – 203
4.48 Pharmaceutical excipients used in the formulation of niacin drug – 204
4.49 Pharmaceutical excipients used in the formulation of
glibenclamide drug – – – – – – – 205
4.49 Pharmaceutical excipients used in the formulation of PABA drug – 206
4.50 Pharmaceutical excipients used in the formulation of erythromycin drug
– – – – – – – – – – 207
4.51 Values of pseudo-first order and second order rate constants for
glibenclamide – DDQ reaction with buffer 2, [DDQ] =10-3M- – 210
4.52 Values of pseudo-first order and second order rate constants for the
formation of erythromycin-DDQ reaction, [DDQ] =10-3M at 30 oC – 212
4.53 Values of pseudo- first order and second order rate constants for
the formation niacin reaction, [DDQ] =10-3M at 30 oC – – 215
4.54 Values of pseudo – first order and second order rate constants for the
formation of PABA reaction, [DDQ] =10-3M at 30 oC – – 218
4.55 Values of pseudo – first order and second order rate constants for the
formation of thiamine-DDQ reaction, [DDQ] =10-3M at 30 oC – – 221
4.56 Effect of temperature on the pseudo-first order rate constant and
activation parameters for the formation of erythromycin-DDQ complex
at ʎmax = 464 nm, [Erythromycin] = 10-2M, [DDQ] = 10-3 M – – 225
4.57 Effect of temperature on the pseudo-first order rate constant and
activation parameters for the formation of glibenclamide-DDQ complex at ʎmax = 464 nm, [Glibenclamide] = 10-2M, [DDQ] = 10-3 – – 230
4.58 Effect of temperature on the pseudo-first order rate constant
and activation parameters for the formation of niacin-DDQ complex
at ʎmax = 464 nm, [Niacin] = 10-2M, [DDQ] = 10-3 M – – – 235
4.59 Effect of temperature on the pseudo-first order rate constant
and activation parameters for the formation of PABA-DDQ complex
at ʎmax = 474 nm, [PABA] = 10-2M, [DDQ] = 10-3 M – – 241
4.60 Effect of temperature on the pseudo-first order rate constant
and activation parameters for the formation of thiamine-DDQ complex
at ʎmax = 474 nm, [Thiamine] = 10-2M, [DDQ] = 10-3 M – – 246
4.61 pH medium on the pseudo-first order rate constant with respect to
the formation of erythromycin-DDQ complex at ʎmax = 464 nm,
[Erythromycin] =10-3M, [DDQ] = 10-4 M – – – – 249
4.62 pH medium on the pseudo-first order rate constant with respect
to the formation of glibenclamide-DDQ complex
at ʎmax = 474 nm, [glibenclamide] =10-3M, [DDQ] = 10-4 M – – 251
4.63 pH medium on the pseudo-first order rate constant with respect
to the formation of niacin-DDQ complex at ʎmax = 464 nm,
[Niacin] =10-3M, [DDQ] = 10-4 M – – – – – 253
4.64 pH medium on the pseudo-first order rate constant with respect
to the formation of PABA-DDQ complex at ʎmax = 474 nm,
[PABA] =10-3M, [DDQ] = 10-4 M – – – – – 255
4.65 pH medium on the pseudo-first order rate constant with respect
to the formation of thiamine-DDQ complex at ʎmax = 474 nm,
[Thiamine] =10-3M, [DDQ] = 10-4 M – – – – 257
4.66 Acid values for the pseudo-first order and second order rate
constant of glibenclamide-DDQ complex at ʎmax = 474 nm, T =
30 oCNaClO4 = 1.02M, [gli]=2.0×10-5 M,[DDQ]=1 x 10-6 M – 259
4.67 Acid values for the pseudo-first order and second order rate
constant of PABA-DDQ complex at ʎmax = 474 nm, T = 30 oC
NaClO4 = 1.02M, [PABA]=2.0×10-5 M,[DDQ]=1 x 10-6 M – – 261
4.68 Acid values for the pseudo-first order and second order rate
constant of niacin-DDQ complex at ʎmax = 474 nm, T = 30 oC
NaClO4 = 1.02M, [Niacin]=2.0×10-5 M,[DDQ]=1 x 10-6 M – – 263
4.69 Acid values for the pseudo-first order and second order rate
constant of thiamine-DDQ complex at ʎmax = 474 nm, T = 30 oC
NaClO4 = 1.02M, [Thiamine]=2.0×10-5 M,[DDQ]=1 x 10-6 M – 265
4.70 Acid values for the pseudo-first order and second order rate constant
of erythromycin-DDQ complex at ʎmax = 474 nm, T = 30 oC NaClO4 =
1.02M, [Erythromycin]=2.0×10-5 M,[DDQ]=1 x 10-6 M – – 267
4.71 Effect of ionic strength on the rate of erythromycin-DDQ reaction
at ʎmax = 464 nm, T = 30 oC ,NaClO4 = 0.1M, [Erythromycin]
= 2.0×10-5 M, [DDQ] =1 x 10-6 M – – – – – 269
4.72 Effect of ionic strength on the rate of glibenclamide-DDQ
reaction at ʎmax = 474 nm, T = 30 oC, NaClO4 = 0.1M, [gli]
=2.0×10-5 M, [DDQ] =1 x 10-6 M – – – – – 271
4.73 Effect of ionic strength on the rate of niacin-DDQ reaction
at ʎmax = 464 nm, T = 30 oC, NaClO4 = 0.1M, [NIA] =2.0×10-5 M,
[DDQ] =1 x 10-6 M – – – – – – – 273
4.74 Effect of ionic strength on the rate of PABA-DDQ reaction
at ʎmax = 474 nm, T = 30 oC, NaClO4 = 0.1M, [PABA] =2.0×10-5 M,
[DDQ] =1 x 10-6 M – – – – – – – 275
4.75 Effect of ionic strength on the rate of thiamine-DDQ reaction at
ʎmax = 474 nm, T = 30 oC, NaClO4 = 0.1M, [THIA] =2.0×10-5 M,
[DDQ] =1 x 10-6 M – – – – – – – 277
4.76 FTIR characterization of glibenclamide-DDQ complex – – – 282
4.77 FTIR characterization of erythromycin-DDQ complex – – 283
4.78 FTIR characterization of PABA-DDQ complex – – – 284
4.79 FTIR characterization of thiamine-DDQ complex – – – 285
4.80 FTIR characterization of thiamine-DDQ complex – – – 286

ABBREVIATIONS

Abbreviation Name
ANOVA Analysis of variance
CT Charge transfer
DDQ 2,3-dichloro-5,6-dicyano-1,4 benzoquinone
ERY Erythromycin
FTIR Fourier transformer infra red
GC Gas chromatography
GLI Glibenclamide
HPLC High performance liquid chromatography
PABA p-aminobenzoic acid or 4-aminobenzoic acid
NIA Niacin
NMR Nuclear magnetic resonance
THF Tetrahydrofuran
THIA Thiamine
TLC Thin layer chromatography
UV-VIS Ultraviolet/visible

CHAPTER ONE
1.0 Introduction
1.1 Charge Transfer Complexation
Acceptors are aromatic systems containing electron withdrawing substituents such as nitro, cyano and halogen groups (Foster, 1967). Electron donors are systems that are electron rich (Ajali and Chukwurah, 2001). The interaction between electron donor and electron acceptor results in formation of charge transfer complex (Ajali et al, 2008). The term charge transfer denotes a certain type of complex which results from interaction of an electron acceptor and an electron donor with the formation of weak bonds (Hassib and Issa, 1996). However the nature of the interaction in a charge transfer complex is not a stable chemical bond and is much weaker than covalent forces. It is better characterized as a weak electron resonance. As a result, the excitation energy of this resonance occurs very frequently in the visible region of the electromagnetic spectrum. This produces the usually intense colour characteristic for these complexes. These optical absorption bands are often referred to as charge transfer bands. Molecular interactions between electron donors and acceptors are generally associated with the formation of intensely coloured charge transfer complexes which absorb radiation in the visible region.Charge transfer (CT) complexes have been widely studied (Ezeanokete et al, 2013; Hala et al, 2013; Frag et al, 2011; Ramzin et al, 2012; Farha, 2013). Charge transfer complexes are known to take part in many chemical reactions like addition, substitution and condensation reactions (Van et al, 2006).
Donor acceptor properties are prerequisites for the formation of charge transfer complexes. Most drugs have –NH or –NH2 groups which behave as bases (electron donors) and could form complexes with acids (electron acceptor).Various cases have been reported. The charge-transfer complexes formed between the ephedrine (Eph) drug as a donor with picric acid (Pi) and quinol (QL) as π–acceptors have been synthesized in methanol as a solvent at room temperature and spectroscopically studied as shown in scheme 1:

 

payment

SPECTROPHOTOMETRIC DETERMINATION OF CHROMIUM(III) AND CHROMIUM(VI) USING 2-[E)-[{3-[(2-HYDROXYBENZYLIDENE) AMINO]PHENYL}IMINO)METHYL]PHENOL

 

ABSTRACT

The Schiff base ligand, 2-[(E)-[{3–[(2-hydroxybenzylidene)amino]phenyl}imino)methyl]phenol was synthesized by condensing 1,3-diaminobenzene and 2-hydroxybenzaldehyde in absolute ethanol. Its Cr(III) and Cr(VI) complexes were equally synthesized. The ligand was characterized via UV, IR and NMR spectroscopy, whereas the complexes were characterized based on UV and IR spectroscopy and conductivity values. Stoichiometric studies indicated 1:1 metal to ligand ratio for both complexes. Cr(III) complex absorbed at 1042.56 cm-1 υ(C-O), 532.37 cm-1 υ(Cr-N) and 607.60 cm-1 υ(Cr-O) while the Cr(VI) complex absorbed at 1182 cm-1 υ(C-O), 749.37 cm-1 υ(Cr-O) and 457 cm-1 for υ(Cr-N).   Based on UV, IR and NMR studies, the ligand coordinated to the metals using the nitrogen and oxygen atoms. Spectrophotometric determination of the metals using the ligand was done at 368 nm for Cr(III)  and 465 nm  for Cr(VI).Optimum conditions for complexation and stability were studied and it was shown that optimum pH for Cr(III) and Cr(VI) were 13.0 and 2.0 respectively. Very few ions such as Co2+, Cu2+, Mn2+, Mg2+, Fe3+ and Zn2+ interfered with the determination. Beer’s law was obeyed between 0.02 to 0.14ppm for both metals. The method was successfully applied in the analysis of steel.

 

 

 

 

 

 

 

TABLE OF CONTENTS

 

Title page        –           –           –           –           –           –           –           –           –           –             i

Approval     –               –           –           –           –           –           –           –           –           –           ii

Declaration      –           –           –           –           –           –           –           –           –           –           iii

Dedication      –           –           –           –           –           –           –           –           –           –           iv

Acknowledgements             –           –           –           –           –           –           –           –           –           v

Abstract          –           –           –           –           –           –           –           –           –           –           vi

Table of contents        –           –           –           –           –           –           –           –           –           vii

List of Tables  –           –           –           –           –           –           –           –           –           –           xi

List of Figures –           –           –           –           –           –           –           –           –           –           xii

List of Schemes          –           –           –           –           –           –           –           –           –          xiii

CHAPTER ONE

1.0   INTRODUCTION         –           –           –           –           –           –           –           –           1

1.1   Spectrophotometry         –           –           –           –           –           –           –           –           1

1.1.1    Beer- lambert’s law     –           –           –           –           –           –           –           –           2

1.2       Schiff Base Ligands   –           –           –           –           –           –           –           –           4

1.2.1   Preparation of Schiff bases      –           –           –           –           –           –           –           4

1.2.2   Uses of Schiff Bases    –           –           –           –           –           –           –           –           6

1.2.3   Biological Importance of Schiff Bases            –           –           –           –           –           7

1.2.4    Schiff Base Metal Complexes            –           –           –           –           –           –           –           8

1.3     Chromium         –           –           –           –           –           –           –           –           –           9

1.3.1   Determination of Chromium    –           –           –           –           –           –           –           9

1.3.2   Uses     –           –           –           –           –           –           –           –           –           –           10

1.4       Statement of the Problem       –           –           –           –           –           –           –           11

1.5       Aims and Objectives               –           –           –           –           –           –           –           12

CHAPTER TWO

2.0 LITERATURE REVIEW            –           –           –           –           –           –           –           –           14

2.1   Catalytic Spectrophotometric Determination of Chromium       –           –           –           14

2.2  Spectrophotometric Determination Of Trace Level Chromium Using Bis

(Salicylaldehyde) OrthophenyleneDiamine In Non-ionic Micellar Media          –           14

2.3  Spectrophotometric Determination of Chromium(III) and chromium(VI)

in sea water.-        –           –           –           –           –           –           –           –           –           15

2.4   Determination of Hexavalent Chromium in drinking water by ion chromatography

with post-column derivatization and UV-visible spectroscopic detection.         –           15

2.5   Determination of Cr(VI) in environmental sample evaluating Cr(VI)

impact in a contaminated area.  –             –           –           –           –           16

2.6   Indirect Extraction – Spectrophotometric Determination of chromium.            –           –           17

2.7   Sensitivity Determination of Hexavalent chromium in drinking water  –           –           18

2.8  Determination of Dissolved Hexavalent Chromium in Drinking Water, Ground Water

and Industrial Waste Water Effluents by Ion Chromatography-            –           –           –           18

CHAPTER THREE

3.0   Experimental       –           –           –           –           –           –           –           –           –           19

3.1   Apparatus            –           –           –           –           –           –           –           –           –           19

3.2   Preparation of Stock Solution     –           –           –           –           –           –           –           19

3.3    Preparation of Buffer Solutions –           –           –           –           –           –           –           20

3.4   Synthesis of the Ligand (HBAPP)         –           –           –           –           –           –           20

3.5  Synthesis of Chromium (III) and Chromium (VI)  Complexes of HBAPP        –            21

3.5.1 Determination of the Stoichiometry of the Complexes by Slope-Ratio Method.         22

3.6  General Procedure for the Complexation Studies           –           –           –           –           23

3.6.1 Effect of Time on the Formation of the Complexes      –           –           –           –           23

3.6.2 Effect of Temperature on the Formation of the Complexes      –           –           –           23

3.6.3 Effect of Concentration of Reagent on the Formation of the Complexes        –           23

3.6.4 Effect of pH on the Formation of the Complexes         –           –           –           –          23

3.6.5 Effect of Interfering Ions on the Formation of the Complexes            –           –           –           23

3.6.6 Calibration Curve-Beer’s Law   –           –           –           –           –           –           –           24

3.7  Determination of Chromium in Alloy      –           –           –           –           –           –           24

3.7.1  Determination of Chromium in Alloy with Flame Atomic Absorption

Spectrophotometry          –           –           –           –           –           –           –           –           24

3.7.2 Determination of Chromium in Alloys with UV Spectrophotometry   –           –           24

 

CHAPTER FOUR

4.0     Results And Discussion            –           –           –           –           –           –           –           26

4.1       Physical Characterization and Molar Conductivity Data of the Ligands and Its

Cr(III) and Cr(VI) Complexes            –           –           –           –           –           –           –           26

4.2     Spectroscopic Characterization Of The Ligand And Its Cr(III) And Cr(VI)

Complexes.       –           –           –           –           –           –           –           –           –           26

4.2.1    Electronic Spectral Data of the Ligand and Its Complexes               –           –           26

4.2.2   Infrared Spectra           –           –           –           –           –           –           –           –           27

4.2.3  1H and 13C NMR Spectra of the Ligand          –           –           –           –           –           28

4.2.4   13C NMR          –           –           –           –           –           –           –           –           –           29

4.2.5   APT (Attached Proton Test)    –           –           –           –           –           –           –           29

4.3     Stiochiomery of the Complexes            –           –           –           –           –           –           30

4.3.1    Metal-Ligand Mole Ratio of Cr(III) Complex           –           –           –           –           30

4.3.2    Metal-Ligand Mole Ratio of Cr(VI) Complex           –           –           –           –           31

4.3.3   Molecular Formulae and Structures of the Ligand and Its Complexes           –           33

4.4      Complexation Studies –           –           –           –           –           –           –           –           35

4.4.1   Effect of Time on the formation of the Complexes    –           –           –           –           35

4.4.2  Effect of the concentration of the reagent on the formation of the complexes           –           36

4.4.3  Effect of temperature on the formation of the complexes       –           –           –           38

4.4.4  Effect of pH on the absorbance of the complexes       –           –           –           –           41

4.4.5  Effect of interfering ions on the formation of Cr(III) and Cr(VI) complexes –           42

4.5     Calibration curve for determination of Cr(III) and Cr(VI) complexes            –           44

4.5.1  Cr(III) complex –           –           –           –           –           –           –           –           –            44

4.5.2  Cr(VI) complex –           –           –           –           –           –           –           –           –           45

4.6    Application using steel solution –           –           –           –           –           –           –           46

4.6.1 Determination of Cr(III) in the steel solution    –           –           –           –           –           47

4.6.2 Determination of Cr(VI) in steel solution          –           –           –           –           –           47

4.7 Conclusion            –           –           –           –           –           –           –           –           –           47

4.8 Recommendation  –           –           –           –           –           –           –           –           –           48

References      –           –           –           –           –           –           –           –           –           –           49

Appendix A    –           –           –           –           –           –           –           –           –           –           55

Appendix B    –           –           –           –           –           –           –           –           –           –           58

 

LIST OF TABLES

3.1: Preparation of Buffer Solution    –           –           –           –           –           –           –           21

4.1: Physical Data of the Ligands and Its Complexes            –           –           –           –           26

4.2: Electronic Spectra            –           –           –           –           –           –           –           –           27

4.3: Infrared Spectral Data of the Ligand and Its Complexes                       –           –           –           28

4.4: 1HNMR Spectral of the Ligand in CDCl3 relative to TMS (ppm)          –           –           28

4.5: 13CNMR Spectral Data of the Ligand   –           –           –           –           –           –           29

4.6. Effect of some interfering ions on Cr(III) Complex       –           –           –           –           43

4.7  Effect of some interfering ions on Cr(VI) complex        –           –           –           –           44

4.8. Determination of Cr(III) in the steel solution-   –            –           –           –           –           –           47

4.9. Determination of Cr(VI) in the steel solution-   –            –           –           –           –           47

4.10. Result of slope-Ratio plot for Cr(III) complex-fixed ligand(1.0X 10-3  M)                 55

4.11. Result of Slope- Ratio plot for Cr(III) complex- fixed metal (1.0 X10-3 M)               55

4.12. Result of Slope-Ratio plot for Cr(VI) complex; fixed ligand (1.0 X 10-3 M)              55

4.13. Result of Slope- Ratio plot for Cr (VI) complex; fixed metal (1.0 X-3M)                   56

4.14.Variation of Absorbance With Time for the Formation of the Complexes                    56

4.15.Variation of Absorbance with Reagent Concentration for the Formation of

Complexes.           –           –           –           –           –           –           –           –           –           56

4.16.Variation of Absorbance with Temperature for the Formation of the

Complexes.          –           –           –           –           –           –           –           –           –           57

4.17. Variation of Absorbance with pH for the Formation of the Complexes.          –           57

4.18   Results of Calibration Curve-Beer’s Law for Cr(III) and Cr (VI) Complexes                        57

 

 

LIST OF FIGURES

4.5: Effect of Time on the formation of Cr(III)complex        –           –           –           –           35

4.6: Effect of Time on the formation of Cr(VI)complex        –           –           –           –           36

4.7: Effect of concentration on the formation of Cr(III) complex                 –           –           37

4.8: Effect of concentration on the formation of Cr(VI) complex                 –           –           38

4.9: Effect of Temperature on the formation of Cr(III)complex        –           –           –           39

4.10: Effect of Temperature on the formation of Cr(VI)complex      –           –           –           40

4.11: Effect of pH on the formation of Cr(III)Complex        –           –           –           –           41

4.12: Effect of pH on the formation of Cr(VI) Complex       –           –           –           –           42

4.13 Calibration curve of Cr(III) complex      –           –           –           –           –           –           45

4.14 Calibration Curve of Cr(VI) Complex    –           –           –           –           –           –           46

 

LIST OF SCHEMES

1  Formation of Schiff  base   –           –           –           –           –           –           –           –           22

2  The ligand  –           –           –           –           –           –           –           –           –           –           33

3 Chromium(III) complex      –           –           –           –           –           –           –           –           34

4  Chromium(VI) complex     –           –           –           –           –           –           –           –           34

 

CHAPTER ONE

INTRODUCTION

 

1.1  SPECTROPHOTOMETRY

Spectrophotometry is the quantitative measurement of the reflection or transmission properties of a material as a function of wavelength1. It is more specific than the general term electromagnetic spectroscopy in that spectrophotometry deals with visible light, near-ultraviolet, and near-infrared, but does not cover time-resolved spectroscopic techniques. Spectrophotometry is a very fast and convenient method of qualitative analysis, due to the fact that absorption occurs in less than one second and can be measured very rapidly. Molecular absorption is valuable for identifying functional groups in a molecule and for the quantitative determination of compounds containing absorbing groups2,3. A spectrophotometer is commonly used for the measurement of transmittance or reflectance of solutions, transparent or opaque solids, such as polished glass or gases. However, they can also be designed to measure the diffusivity of any of the listed light ranges that usually cover around 200 – 250 nm using different controls and calibrations1 .

The most common spectrophotometers are used in the UV and visible regions of the spectrum and some of these instruments also operate into the near-infrared region as well. Visible region (400 – 700 nm) spectrophotometry is used extensively in colorimetry science. Ink manufacturers, printing companies, textile, vendors and many more, need the data provided through colorimetry. They take readings in the region of every 5 – 20 nanometers along the visible region and produce a spectral reflectance curve or a data stream for alternative presentations.

Spectrophotometeric method is undoubtedly the most accurate method for determining, among other things, the concentration of substances in solution, but the instruments are of necessity more expensive. A spectrophotometer may be regarded as a refined filter photoelectric photometer which permits the use of continuously variable and more nearly monochromatic bands of light. The essential parts of a spectrophotometer are (1) a source of radiant energy (2) a monochromator i.e. a device for isolating monochromatic light or, more accurately, narrow bands of radiant energy from the light source (3) glass or silica cells for the solvent and for the solution under test and (4) a device to receive or measure the beams of radiant energy passing through the solvent4.

Infrared (IR)5 light is electromagnetic radiation with longer wavelengths than those of visible light, extending from the nominal red edge of the visible spectrum at 700 nm to 1mm. Infrared spectroscopy is very useful for obtaining qualitative information about molecules. For absorption in infrared region to occur, there must be a change in the dipole moment (polarity) of the molecule. Absorbing groups in the infrared region absorb within a certain wavelength region, and the exact wavelength will be influenced by neighbouring groups. Their absorption peaks are much sharper than the ultraviolet or visible regions and easier to identify. The most important use of infrared spectroscopy is in identification and structure analysis; it is useful for qualitative analysis of complex mixtures of similar compounds because some absorption peaks for each compound will occur at a definite and selective wavelength, with intensities proportional to the concentration of absorbing species.

Nuclear magnetic resonance spectroscopy5 is a research technique that exploits the magnetic properties of certain atomic nuclei. It measures the absorption of electromagnetic radiation in the radiofrequency region of roughly 4 MHz to 750 MHz, nuclei of atoms rather than outer electrons are involved in the absorption process. It determines the physical and chemical properties of atoms or the molecules in which they are contained. It relies on the phenomenon of NMR and can provide detailed information about the structure, dynamics, reaction state and chemical environment of molecules. NMR is used to investigate the environment of molecules. NMR is used to investigate the properties of organic molecules, although it is applicable to any kind of sample that contains nuclei possessing spin.

  • Beer- Lambert’s Law

payment

SOLVENT EXTRACTION STUDIES ON Zn(II) AND Cd(II) COMPLEXES OF 1,5-DIMETHYL-2-PHENYL-4[(E)-(2,3,4-TRIHYDROXYPHENYL)]DIAZENYL-1,2-DIHYDROXYL-3H-PYRAZOL-3-ONE

ABSTRACT

The azo-ligand, 1,5-dimethyl-2-phenyl-4-[(E)-(2,3,4-trihydroxylphenyl) diazenyl]-1,2-dihydro-3H-pyrazol-3-one (H3L) and its Zn(II) and Cd(II) complexes have been synthesized and characterized based on stoichiometric, molar conductance, electronic and infra-red spectral studies. The results showed that H3L reacted with the metals in 2:1 ratio. H3L coordination was through the hydroxyl, azo and carbonyl groups to form [Zn(H2L)2]2+ and [Cd(H2L)2]2+ respectively. Solvent extraction studies on Zn(II) and Cd(II) using 1,5-dimethyl-2-phenyl-4-[(E)-(2,3,4-trihydroxylphenyl) diazenyl]-1,2-dihydro-3H-pyrazol-3-one were carried out with  CHCl3. Effects of other extraction variables like, pH, salting-out agent, masking agent and acids were also investigated. Cd(II) was quantitatively extracted in 0.001 M HCl up to 100%; and 0.001 M of either thiocyanate, or 0.001 M tatrate masked Cd(II) up to 90%, under five minutes. Extraction of Zn(II) with H3L/CHCl3 was quantitative in 0.001 M HCl up to 96% under seventy minutes. In the same vein, 1 M cyanide and 1 M thiocyanate masked it up to 79% and 67% respectively. Cd(II) was successfully separated from Zn(II) following four-cycle extraction up to 96.5%  in 0.001 M HCl using H3L/CHCl3 in the presence of 1 M cyanide. Recovery of Zn(II) and Cd(II) from rubber carpet was up to 90% and 85% respectively under the established parameters. The extraction constant was established for both Zn(II) and Cd(II) complexes from the results obtained from pH, where the slope was 0.141 and 0.0516, and the extraction constant 7.316 and 3.899 respectively. Hence, H3L is a promising extractant for Zn(II) and Cd(II) ions.

 

CHAPTER ONE

  •                               INTRODUCTION

During the years 1900 to 1940, solvent extraction was mainly used by the organic chemist for separating organic substances. Since in these systems, the solute, (desired component) often exist in only one single molecular form, such system are referred to as non- reactive system1. However, it was also discovered that mainly weak acids could complex metals in the aqueous phase to form complex soluble in organic solvent. This is an indication that organic acid may be taken from the aqueous or the organic phase; such system is referred to as reactive system. This has become a tool for analytical chemist, when the extracted metal complex showed a specific colour that could be identified spectrometrically.

Solvent extraction is a process whereby two immiscible liquids are vigorously shaken in an attempt to disperse one in the other so that solutes can migrate from one solvent to the other2. When the two liquids are not shaken the solvent to solvent interface area is limited to the geometric area of the circle separating the two solvents. However as the two liquids are vigorously shaken the solvents become intimately dispersed in each other. The dispersal is in the form of droplets. The more vigorous the shaking the smaller the droplets will be. The smaller the droplets are, the more surface area there is between the two solvents. The more the surface area between the two solvents, the smaller the linear distance will be that molecules will travel to reach the other solvent and migrate into it. The shorter the linear distance travelled by the molecules, the more rapid will be the extraction. The fundamental reason for molecules to migrate from one phase into another is solubility. The molecules will preferentially migrate to the solvent where they have the greatest solubility. If the molecules are very polar they will generally favour the aqueous phase. If the molecules are non-polar they will favour the organic phase. The key concept to take away at this point is that the process of solvent extraction requires that the chemist adjust the solution conditions so that the radionuclide of interest is in the proper oxidation state and the solution pH is adjusted so that the appropriate complexing agent will form a neutral complex that will easily migrate into the organic phase based on those chemical conditions1.

Solvent extraction has been used predominantly for the isolation and pre-concentration of a single chemical species prior to its determination3; it may also be applied to the extraction of group of metals or classes of organic compounds, prior to their determination by techniques such as atomic absorption or chromatography. Solutes have differing solubilities in different liquids due to variation in the strength of the interaction of solute molecules with those of the solvent. For this reason, the choice of solvent for extraction is governed by the following4:

  1. A high distribution ratio for the solute and a low distribution ratio for undesirable impurity.
  2. Low solubility in the aqueous phase.
  3. Sufficient low viscosity and sufficient density difference from the aqueous phase to avoid the formation of emulsion.
  4. Low toxicity and flammability.
  5. Ease of recovery of solute from the solvent for subsequent analytical processing. Thus the boiling point of the solvent and the ease of stripping by chemical reagents merit attention when a choice is possible. Sometimes, mixed solvent may be used to improve the above properties; and salting-out agent may also improve extractability.

1.1            The Solvent Extraction Process

payment

RISK ASSESSMENT OF SELECTED HEAVY METAL CONTAMINANTS IN PADDY SOIL AND RICE SAMPLES FROM TWO FARMS IN EDDA AFIKPO SOUTH LGA EBONYI STATE NIGERIA

 

CHAPTER ONE

1.0       INTRODUCTION

1.1       Background of study:

The study of heavy metals by scientists have intensified over the last two decades, this is partly owing to its usefulness in the preparation of many inorganic complexes, and  even more importantly, because of their health effects as  bio-accumulative toxic materials (Duruibe et al., 2007). Personal recent survey has shown the study of heavy metals to have cut across different fields and diverse applications, including; pharmaceutical analysis, food analysis, water analysis (both wastewater and portable water), soil analysis, metallurgical analysis, as well as electrical and electronics material analysis. This level of widespread analysis of this group of metals underscores their importance and the dependability of man on products that have direct or indirect association with them. Considering the widespread means of heavy metal contamination, it will be correct to infer that our environment is constantly and seriously under the threat of heavy metal pollution (GWRTAC, 1997). Soils are the major sinks for heavy metals released into the environment and unlike organic contaminants which are oxidized to carbon (IV) oxide by microbial action, most metals, and especially heavy metals do not undergo microbial or chemical degradation (Kirpichtchikova et al., 2006), and the total concentration of these heavy metals in soil persist for a long time after their introduction (Adriano, 2003), changes in their chemical forms (speciation) and bioavailability are, however, possible. Soil as a component of the terrestrial ecosystem, being essential for the growth of plants is a dynamic system and is subject to short term fluctuations, such as variation in moisture status and pH and also undergoes gradual alterations in response to changes in management and environmental factors (Abubakar and Ayodele, 2002). The high level of civilization related soil pollution has recently become a major issue and chemical analysis of soil is important for environmental monitoring and legislation (Iwegbue et al., 2004). According to McLaughlin et al., (2000), Heavy metal contamination of soil may pose risks and hazards to humans and the ecosystem through the following means:

  • direct ingestion or contact with contaminated soil
  • the food chain (soil-plant-human or soil-plant-animal-human)
  • drinking of contaminated ground water
  • reduction in food quality (safety and marketability)
  • reduction in land usability for agricultural production causing food insecurity

Today it is generally recognized that the particular behaviour of metals in the environment is determined by their specific physicochemical forms rather than by their total concentration. Several chemical speciation and fractionation methods for heavy metal analysis in soils and sediments have been and are still being developed and applied (Fillip et al., 1995).  They are primarily used to understand the particular environmental behaviour of metals, present in a variety of forms and in a variety of matrices (Fillip et al., 1995).

Rice is the world’s most important staple food crop consumed by more than half of the world population as represented by over 4.8 billion people in 176 countries with over 2.89 billion people in Asia, over 150.3 million people in America and over 40 million people in Africa (FAO, 1991; Bruntrup et al., 2016). It is an important food commodity for most people in sub-Saharan Africa particularly West Africa where the consumption of cereals, mainly sorghum and millet has decreased from 61% in the early 1970’s to 49% in the early 1990’s while that of rice has increased from 15% to 26% over the same period (Jones, 1981, FAO 2001). In Nigeria, the demand for rice has been on the increase since the mid 1970 (Daramola, 2005). During the 1960’s, Nigeria had a per capita annual rice consumption of 3 kg which increased to an average of 18 kg during the 1980’s, reaching 22 kg in the latter half of the 1990’s (FAO, 2001; Akpokodje et al., 2001). Since the mid-1980’s, rice consumption has increased at an average annual rate of 11% with only 3% explained by population growth (FAO, 2001), Also, within the decade of the 1990’s, Erenstein et al. (2003) reported a 14% annual increase in the demand for rice in Nigeria. The substitution of rice for coarse grains and traditional roots and tubers shifted the demand for rice to an average annual growth rate of 5.6% between 1961 and 1992 (Osiname, 2002). An interesting reason for rice being very popular as suggested by nutritionists is its ease of digestion and the fact that rice provides 21% of global human per capita energy and 15% of per capita protein (Nwinya et al., 2014). It is low in fat and protein, compared with other cereal grains. Recent studies by the modern nutritionists have compared the easily digestible organic rice protein, a highly digestible and non-allergenic protein to mother’s breast milk in the aspect of its nutritious quality and also for the high quantity of amino acid that is common in both rice protein and breast milk (Erenstein et al., 2003). Rice also provides minerals, vitamins and fiber, although, all constituents except carbohydrates are reduced by milling.

Many literatures on rice consumption have been mainly concerned with the nutritional analysis, neglecting the obvious health issues posed by many possible contaminants in the product. Considering the uncertain environmental arrangement of the Nigeria’s lithospheric and atmospheric space, that is, the poor spacing and demarcation of business areas, agricultural areas, industrial areas and residential areas in Nigeria, as well as the constituents of most agro-chemicals used in rice cultivation, it becomes imperative to extend and sustain research on the possible contaminants in rice, grown and produced in Nigeria.

payment

 

QUALITY CHARACTERISTICS OF UNDERGROUND WATER RESOURCES IN NKANU EAST AND NKANU WEST LOCAL GOVERNMENT AREAS OF ENUGU STATE, NIGERIA

ABSTRACT

Physicochemical and bacteriological analyses of underground water resources in Nkanu East and Nkanu West Local Government Areas of Enugu state,  Nigeria were carried out to evaluate the potability and quality of the rural water supplies and to provide baseline data for future quality assessment. Underground water samples were collected from ten different boreholes in Nkanu East and Nkanu West LGAs. The parameters measured include temperature, colour, pH, electrical conductivity, turbidity, total dissolved solids, total hardness, calcium hardness, magnesium hardness, total alkalinity, chloride, sulphate, phosphate, nitrate, sodium, potassium, lead, chromium, copper, cadmium, nickel, iron, zinc and total coliform. The water showed near neutral pH (6.4- 8.2) favourably comparable to the WHO recommended range of 6.5-8.5, with moderate permanent hardness of 2.5-289 mg/L. Conductivity and total dissolved solids values for Amechi Idodo (4360 μs/cm, 2650 mg/L) and Mbulu Owo (4880 μs/cm, 2930 mg/L) were higher than the WHO guideline values of 1660 μs/cm and 1000 mg/L, respectively. Concentrations of most trace metals and all anions were below the WHO guideline values. However, iron,cadmium and chromium occurred at levels slightly above the WHO permissible limit. Total coliform count in Amechi Idodo and Mbulu Owo exceeded the WHO guideline value of zero. The underground waters studied are good for drinking provided they are boiled to remove microbial contamination.

 

TABLE OF CONTENTS

                                                                                      Pages

 

Title Page————————————————————————— i

Approval Page——————————————————————— ii

Certification———————————————————————— iii

Dedication————————————————————————– iv

Acknowledgement—————————————————————- v

Abstract—————————————————————————– vi

Table of Contents———————————————————-   —- vii

List of Tables———————————————————————- xi

List of Figures——————————————————————— xii

 

CHAPTER ONE

  • Introduction——————————————————————- 1

1.1 Underground water quality————————————————- 1

1.2 Background of Study——————————————————– 2

1.3 Scope of Study—————————————————————- 3

1.4 Objective of Study———————————————————– 4

 

CHAPTER TWO

  • Literature Review————————————————————- 5

2.1 Water————————————————————————— 5

2.1.1 Properties of water——————————————————— 5

2.1.2 Uses of Water ————————————————————– 6

2.2 Types of water resources—————————————————- 7

2.2.1 Underground water——————————————————– 7

2.2.2 Surface water————————————————————— 8

2.2.3 Water in the atmosphere————————————————- 12

2.3 Pollution ———————————————————————- 12

2.3.1 Water pollution————————————————————- 13

2.3.1.1 Organic pollutants——————————————————- 13

2.3.1.2 Inorganic pollutants—————————————————– 15

2.3.1.3 Sediments pollutants ————————————————— 16

2.3.1.4 Radioactive materials ————————————————– 16

2.3.1.5 Thermal pollutants —————————————————– 17

2.3.2 Underground water pollution/pollutant ——————————- 17

2.3.2.1 Point-source pollution ————————————————- 19

2.3.2.2 Non-point source pollution——————————————– 19

2.3.2.3 Chemical pollution—————————————————— 21

2.3.2.4 Biological pollution—————————————————– 22

2.3.2.5 Physical/Natural pollution ——————————————– 24

2.4 Water Analysis ————————————————————— 25

2.4.1 Physical examination—————————————————— 25

2.4.1.1 Temperature ————————————————————- 25

2.4.1.2 Turbidity —————————————————————– 25

2.4.1.3 pH————————————————————————– 27

2.4.1.4 Total dissolved solids ————————————————— 27

2.4.1.5 Conductivity————————————————————– 28

2.4.1.6 Colour——————————————————————— 28

2.4.2 Chemical examination ————————————————— 28

2.4.2.1 Hardness —————————————————————— 28

2.4.2.2 Alkalinity—————————————————————– 30

2.4.2.3 Calcium——————————————————————- 30

2.4.2.4 Magnesium————————————————————— 31

2.4.2.5 Chloride——————————————————————- 31

2.4.2.6 Nitrate——————————————————————— 31

2.4.2.7 Phosphate—————————————————————– 32

2.4.2.8 Potassium—————————————————————– 32

2.4.2.9 Sulphate——————————————————————- 33

2.4.2.10 Sodium——————————————————————- 33

2.4.2.11 Cadmium—————————————————————- 34

2.4.2.12 Chromium————————————————————— 35

2.4.2.13 Copper——————————————————————– 36

2.4.2.14 Iron———————————————————————– 37

2.4.2.15 Lead———————————————————————- 38

2.4.2.16 Nickel——————————————————————– 38

2.4.2.17 Zinc———————————————————————– 39

2.4.3 Microbiological examination ————————————– `—- 39

 

CHAPTER THREE

  • Materials and Methods —————————————————— 41

3.1 Sample collection———————————————————— 41

3.2 Method of analysis ———————————————————- 43

3.2.1 Turbidity ——————————————————————– 43

3.2.2 Temperature —————————————————————- 43

3.2.3 Colour———————————————————————— 43

3.2.4 Total dissolved solid —————————————————— 43

3.2.5 pH—————————————————————————– 44

3.2.6 Conductivity—————————————————————- 44

3.2.7 Total alkalinity————————————————————- 44

3.2.8 Total hardness————————————————————– 45

3.2.9 Calcium———————————————————————- 46

3.2.10 Magnesium—————————————————————- 47

3.2.11 Chloride——————————————————————– 47

3.2.12 Nitrate———————————————————————- 48

3.2.13 Sulphate——————————————————————– 49

3.2.14 Phosphate—————————————————————— 49

3.2.15 Sodium——————————————————————— 50

3.2.16 Potassium—————————————————————— 50

3.2.17 Heavy metals determination ——————————————- 51

3.2.18 Bacteriological examination——————————————– 52

CHAPTER FOUR

4.0 Results and Discussions—————————————————– 53

4.1 Turbidity———————————————————————– 55

4.2 Colour————————————————————————– 55

4.3 Conductivity—————————————————————— 57

4.4 Total dissolved solid——————————————————— 57

4.5 pH——————————————————————————- 58

4.6 Total hardness, calcium hardness and magnesium hardness——— 59

4.7 Total alkalinity—————————————————————- 61

4.8 Nitrate————————————————————————– 62

4.9 Phosphate———————————————————————- 62

4.10 Sulphate———————————————————————- 63

4.11 Chloride———————————————————————- 63

4.12 Sodium and potassium—————————————————– 64

4.13 Heavy metals—————————————————————- 67

4.14 Total coliform————————————————————— 69

Conclusion and Recommendation ——————————————– 69

References ————————————————————————- 71

LIST OF TABLES

 

3.1: Sample code and sample location—————————————- 41

 

4.1: WHO standard values for drinking water——————————- 53

 

4.2: Physicochemical quality of underground water in Nkanu East and Nkanu West Local Government Areas, Enugu State, Nigeria—————————————————–        —- 54

 

4.3: Colour and turbidity of water sample————————– – 56—-

4.4: Conductivity and total dissolved solid of water sample————– 58

 

4.5: Total hardness, magnesium hardness and calcium hardness of water sample——————————————————– 60

 

4.6:  Metal concentrations (mg/L) of water sample ———————— 66

 

LIST OF FIGURES

 

3.1: Map of Nkanu East and Nkanu West LGAs ————————— 42

4.1 Bar-chart showing correlation between colour and turbidity- 56

4.2 Bar-chart showing correlation between conductivity and total

dissolved solids—————————————————– 58

4.3: Bar-chart showing correlation between total hardness,

magnesium hardness and calcium hardness——————— 61

 

CHAPTER ONE

  • Introduction

1.1 Underground water quality

Water is the matrix of life and forms the bulk of the weight of the living cells. The resources of usable water have been diminishing and are unable to meet the variety of needs of modern civilization. Water as the carrier of pathogenic microorganisms, can cause immense harm to public health. Waterborne diseases include typhoid and paratyphoid fever, dysentery and cholera, polio and infectious hepatitis [1].

Many developing countries are witnessing a stage of development where water from shallow wells and boreholes are gradually supplementing the original sources of drinking water (surface water). The preference for underground water to surface water is borne out of the belief that before underground water can be distributed as tap water it must always be subjected to some purification, while in practice, underground waters are filtered by natural processes as they pass through columns of soils, sands, strata, or sedimentary layers of rocks and are usually clear of solid materials as they come from the aquifer, particularly if they are deep seated ones. The intricate pore spaces or water passage ways of the aquifer materials act as a fine filter and remove small particles of clay or any other fines [2]. Organic materials decay or are destroyed in transit. Thus, the dirtiest and most polluted sewage water may become clear of suspended/particulate solid materials once it has gone through a thick bed of sand or geologic and pedologic units. As a result of this natural self-cleansing of polluted water by deep-seated aquifers, physical and biological aspects of pollution may not pose serious problems in underground waters [2].

Thus, underground water may not be treated before use and is believed to be free from pollution. In spite of all this, underground waters may have pollutants that not only depend on the geology, pedology, and mineralogy of the formations it flows through but also on the constituent pollutants/contaminants in the water that recharges the underground water. Unsatisfactory colour and taste are easily detected and are good indicators for underground waters of poor quality. Some underground waters taste of iron, others may have a disagreeable odor. Borehole waters must, as a rule, be analyzed for chemical contaminants before the water is distributed and supplied to households [2].

 

1.2 Background of Study

       The area of study is Nkanu East and Nkanu West. A Local Government Area in Enugu State, Nigeria, Nkanu  East  borders  Ebonyi State to the east. Its Headquarters is Amagunze. It is a rural area with a population of about 148, 774 and land mass of approximately 795 km2.. Nkanu West has its Headquarters at Agbani. It has an area of 225 km2 and a population of 146,695. The major occupation in these areas is farming. The various communities making up the two local government areas live in small villages, which still have considerable natural surroundings. Although there are springs and streams, most of the communities rely on boreholes for their water supply due to proximity and modernity [3].

 

payment

PRODUCTION, OPTIMIZATION AND APPLICATION OF PRINTING INK FROM WASTE CARBON SOURCES

TABLE OF CONTENTS

 

Title page        –           –           –           –           –           –           –           –           –           –           i

Approval page –           –           –           –           –           –           –           –           –           –           ii

Certification    –           –           –           –           –           –           –           –           –           –           iii

Dedication      –           –           –           –           –           –           –           –           –           –           iv

Acknowledgement      –           –           –           –           –           –           –           –           –           v

Table of contents        –           –           –           –           –           –           –           –           –           vi

List of tables   –           –           –           –           –           –           –           –           –           –           ix

List of figures –           –           –           –           –           –           –           –           –           –           x

List of abbreviations, symbols and notations –           –           –           –           –           –           xi

Abstract          –           –           –           –           –           –           –           —          –           –           xii

Chapter 1: INTRODUCTION

Historical overview     –           –           –           –           –           –           –           –           –           1

Writing ink and preservation  –           –           –           –           –           –           –           –           5

Ink composition          –           –           –           –           –           –           –           –           –           7

Printing ink     –           –           –           –           –           –           –           –           –           –           17

Printing ink and processes      –           –           –           –           –           –           –           –           18

Manufacturing process description     –           –           –           –           –           –           –           23

Statement of problems            –           –           –           –           –           –           –           –           28

Aim/objectives of the study    –           –           –           –           –           –           –           –           28

Scope/limitation of the study  –           –           –           –           –           –           –           –           28

CHAPTER 2: LITERATURE REVIEW

Background    –           –           –           –           –           –           –           –           –           –           29

Carbon black   –           –           –           –           –           –           –           –           –           –           30

Conversion of waste tyre into carbon black   –           –           –           –           –           –           34

Reprocessing of used tyres into activated carbon and other products           –           –           35

The Improvement of carbon black from waste tyres for offset printing ink

using coupling agent   –           –           –           –           –           –           –           –           –           38

Ink chemistry and processes   –           –           –           –           –           –           –           –           38

The science of colours –           –           –           –           –           –           –           –           39

Pigments         –           –           –           –           –           –           –           –           –           –           42

Pigments and dyes      –           –           –           –           –           –           –           –           –           53

Linseed oil      –           –           –           –           –           –           –           –           –           –           54

Drying oils for printing inks    –           –           –           –           –           –           –           –           57

Chemistry of drying oils         –           –           –           –           –           –           –           –           58

Drying process of printing ink            –           –           –           –           –           –           –           60

CHAPTER 3: MATERIALS AND METHODS

Materials/Apparati      –           –           –           –           –           –           –           –           –           66

Reagents and chemicals          –           –           –           –           –           –           –           –           67

Methods          –           –           –           –           –           –           –           –           –           –           67

Ink manufacture          –           –           –           –           –           –           –           –           –           70

Ink printing tests         –           –           –           –           –           –           –           –           –           71

Images of instruments used and processes     –           –           –           –           –           –           72

CHAPTER 4: RESULTS AND DISCUSSION

Carbon black samples images as obtained                  –           –           –           –           –           75

Properties of carbon black produced  –           –           –           –           –           –           –           77

Viscosity results          –           –           –           –           –           –           –           –           –           80

Press ink test results    –           –           –           –           –           –           –           –           –           81

Effect of temperature on printing performance\         –           –           –           –           –           81

Effect of temperature on viscosity     –           –           –           –           –           –           –           82

Temperature effects on ink flow         –           –           –           –           –           –           –           83

Mathematical model   –           –           –           –           –           –           –           –           –           84

Viscosity-temperature model  –           –           –           –           –           –           –           –           84

Conclusion/summary   –           –           –           –           –           –           –           –           –           85

Glossary          –           –           –           –           –           –           –           –           –           –           87

References      –           –           –           –           –           –           –           –           –           –           89

Appendix

 

LIST OF TABLES

 

1.1       Use of inorganic pigments      –           –           –           –           –           –           –           9

1.2       Solvent and binder combinations       –           –           –           –           –           –           15

1.3       Printing ink, drying systems and vehicles       –           –           –           –           –           19

2.1       Countries and their capacity production of carbon black       –           –           –           34

2.2       Refractive index of some very popular class of inorganic pigments  –           –           44

2.3       Properties of various kinds of pigments         –           –           –           –           –           47

2.4       Differences between organic and inorganic pigments            –           –           –           51

2.5       Differences between dyes and pigments        –           –           –           –           –           53

2.6       Drying oils and % weight       –           –           –           –           –           –           –           57

2.7       Possible fatty acids in oils and their structures           –           –           –           –           59

3.1       Ink percentage composition    –           –           –           –           –           –           –           71

4.1       Produced Ink properties         –           –           –           –           –           –           –           77

4.2       Ink viscosity    –           –           –           –           –           –           –           –           –           80

LIST OF FIGURES

Figure 1.1        Chinese ink stick         –           –           –           –           –           –           –           5

Figure 1.2        Pigments for coloured printing inks    –           –           –           –           –           10

Figure 1.3        Flow diagram of the ink manufacturing process        –           –           –           24

Figure 2.1        Additive primary colours        –           –           –           –           –           –           40

Figure 2.2        Subtractive primary colours    –           –           –           –           –           –           41

Figure 2.3        Chromophores –           –           –           –           –           –           –           –           45

Figure 2.4        Structure of a triglyceride found in linseed oil           –           –           –           55

Figure 3.1        Flow diagram for pigment sample preparation           –           –           –           69

Figure 3.2        Electrical furnace used for pyrolysis, before use        –           –           –           72

Figure 3.3        Electrical furnace, while in operation –           –           –           –           –           72

Figure 3.4        Digital viscometer with thermostat     –           –           –           –           –           73

Figure 3.5        Refluxing process       –           –           –           –           –           –           –           73

Figure 3.6        Mixing board, scrapper and spatula    –           –           –           –           –           73

Figure 3.7        Production in progress            –           –           –           –           –           –           74

Figure 4.1        Graphite rods before pulverizing        –           –           –           –           –           75

Figure 4.2        Coal sample     –           –           –           –           –           –           –           –           75

Figure 4.3        Shredded tyre before pyrolysis           –           –           –           –           –           75

Figure 4.4        Pyrolyzed tyre –           –           –           –           –           –           –           –           75

Figure 4.5        Furnace carbon black  –           –           –           –           –           –           –           76

Figure 4.6        Graphite rod carbon black      –           –           –           –           –           –           76

Figure 4.7        Tyre carbon black        –           –           –           –           –           –           –           76

Figure 4.8        Coal carbon black       –           –           –           –           –           –           –           76

Figure 4.9        Ink viscosities versus temperature      –           –           –           –           –           82

 

ABBREVIATIONS, SYMBOLS AND NOTATIONS

ASTM – American society for testing and materials

BHA   – Butylated hydroxyanisole

BHT    – Butylated hydrotoluene

CMYK  – Cyan, magenta, yellow and black

CdS     – Cadmium sulphide

DOP    – Di-Octyl phthalate

EDTA – Ethylene di-amine tetra-acetic acid

EDX    – Energy dispersive x-ray

FCC    – Fluid catalytic cracking

FFA     – Free fatty Acid

IARC  – International agency for research on cancer

MEK   – Methyl ethyl ketone

MIBK – Methyl isobutyl ketone

PAH    – Polycyclic aromatic hydrocarbon

PE       – Polyethylene

PG       – Propyl Gallate

SBR    – Styrene butadiene

TBHQ – Tert-butyl hydroquinone

UV      – Ultra violet

VOC   – Volatile organic compounds

VM&P            -Varnish makers’ and painters’

mPa.s – milli-Pascal-second

nm/µm – nanometer / micro-meter

 

ABSTRACT

 Production of carbon black from novel sources like spent automobile tyre, anthracite coal, furnace soot and graphite rod and subsequent use in the production of offset printing inks has been investigated. Carbon black from these sources were obtained by pyrolysis of shredded spent tyre and coal samples at 750-900oC in an electrical furnace, isolation of furnace carbon black and graphite rod from dry cell, drying and pulverization of the resulting samples. Acid demineralization of the samples for 24hr followed with distilled water rinsing and oven drying at 110oC for 12 hr were also carried out before sieving. The production of offset printing ink from the synthesized carbon black samples each of particles <37µm was done by oleoresinous varnish preparation method using a product formula. Viscosities of the produced ink were measured at room temperature (18000 mPa.s) and viscosity-temperature variation of the ink was determined as well. The ink showed viscosity–temperature stability at higher temperature (≥ 35oC). Tests such as viscosity, dispersion, shade, drying, adhesion, scratch resistance, gloss, flexibility, water resistance, heat resistance, opacity, transparency, and tack were carried out, being dictated by their end use. Printability and product consistency with imported black ink were verified. The produced ink quality showed a little variation with the imported ink. However, the results indicate that inks of carbon black from furnace and tyre <37µm size gave the best result besides their blends whereas carbon black from coal and graphite rod of the same size gave fair results.

CHAPTER 1

 1.0       INTRODUCTION

Ink is a liquid or paste that contains pigments and or / dyes and is used to colour a surface to produce an image, text or design. Ink is used for drawing and / or writing with pen, brush, or quill. Thicker inks, in paste form, are used extensively in letter press and lithographic printing. Chemists view it as a colloidal system of fine pigment particles dispersed in a solvent1. The pigment may or may not be coloured, and the solvent may be aqueous or organic.

Ink can be a complex medium, composed of solvents, pigments, dyes, resins, lubricants, solubilizers, surfactants, particulate matter, flourescers, and other materials. The components of inks serve many purposes; the ink’s carrier, colourants and other additives control flow and thickness of the ink and its appearance when dry.

1.1       HISTORICAL OVERVIEW

The origins of printing can be traced back several centuries. Pictorial prints were produced from cut wood blocks in Japan during the tenth century and probably earlier in China. The first movable type, moulded in clay, can be traced to China in the eleventh century, and wooden type appeared in China in the fourteenth century. In Europe, book production from wood blocks was seen early in the fifteenth century, and Gutenberg introduced cast metal type in the middle of the fifteenth century. These inventions were the basis of the original printing method, namely letterpress printing.

 

payment

PHYTOCHEMICAL QUANTIFICATION, ANTIOXIDANT AND ANTIMICROBIAL ACTIVITIES OF ROOT EXTRACTS OF DENNETTIA TRIPETALA AND MILICIA EXCELSA

ABSTRACT

The roots of Dennettia tripetala and Milicia excelsa were analyzed for the presence of phytochemicals. Five different solvents, which include methanol, ethanol, ethyl acetate, butanol and water, were used for the extraction of the phytochemicals.The root of Dennettia tripetala contained alkaloids, terpenoids, flavonoids, saponins, phenols, steroids and glycosides in varying degrees of abundance in the different solvents with tannins not detected in all the solvents. Milicia excelsa contained all the phytochemicals in Dennettia tripetala, in addition to tannins, in different degrees of abundance in the various solvents. The root of Dennettia tripetala contained 1.83 % alkaloids, 3.64 % flavonoids, 1.41 % saponins, 0.67 %phenols, 0.36 % steroids and 0.08 % glycosides whereas that of Milicia excelsa contained 2.19 %alkaloids, 6.40 % flavonoids, 0.87 %  saponins, 0.34 % phenols, 0.36 % tannins, 0.15 % steroids and 0.09 % glycosides. Results of the Principal Component Analysis (PCA) of the phytochemicals revealed that, in Dennettia tripetala, there was strong positive correlation between alkaloids and glycosides (0.995)and also phenols and saponins (1.000) while the strong negative correlations were between alkaloids and flavonoids (-0.980), flavonoids and glycosides (-0.956), phenols and steroids (-1.000) and also saponins and steroids (-1.000). In Milicia excelsa, the strong positive correlations were between alkaloids and flavonoids (0.908), phenols and saponins, glycosides (0.866) and also steroids and tannins (1.000) whereas the strong negative correlations were between phenols and steroids (-0.866), saponins and tannins, steroids (-1.000) as well as tannins and phenols (-0.866). An assay of the antioxidant potentials of various extracts of both plants, using 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging method, revealed that the ethanolic extracts of Dennettia tripetala and Milicia excelsa as well as the methanolic extract of Dennettia tripetala showed high percent inhibition ranging from 83.34 to 89.75 at 0.01 mg/mL of the extracts; results which showed to be better than standard ascorbic acid (67.89) at the same concentration. Other extracts of both plants, at higher concentrations, gave percent inhibitions ranging from 35.80 for the butanolic extract of Milicia excelsa at 0.025 mg/mL to 95.96 for the methanolic extract of the same plant at 0.5 mg/mL. A comparison of the half maximal inhibitory concentration (IC50) values of the extracts showed that ethyl acetate extracts of both plants had the best IC50 values at 0.014 and 0.150 for Dennettia tripetala and Milicia excelsa respectively which were better than ascorbic acid standard whose IC50 value was 1.060. All the other extracts of both plants also had IC50 values better than ascorbic acid except for ethanol in both plants and methanol in Milicia excelsa. The extracts were tested for antimicrobial activity against a gram positive cocci, staphylococcus aureus, and a gram negative rod, klebsiella sp. The results revealed that the ethanolic extract of Dennettia tripetala and the butanolic extracts of both plants showed activity against the test organisms at two concentrations, 400 mg/mL and 200 mg/mL, with the inhibition zone diameters (IZD) ranging from 8.2 mm to 12.0 mm and 6.5 mm to 14.0 mm for the ethanolic and butanolic extracts respectively. The minimum inhibitory concentration (MIC) of the extracts ranged from 41.5 mg/mL to 48.3 mg/mL for the ethanolic extracts and 164.8 mg/mL to 111.7 mg/mL for the butanolic extracts. The presence of these secondary metabolites in varying and substantial amounts in the roots of the plants as well as the antioxidant and antimicrobial potentials of the roots of the plants lends scientific credence to the ethnomedicinal use of these plants parts for the treatment of various diseases and ailments.

 

TABLE OF CONTENTS

Title page                                                                                                                                 i

Certification                                                                                                                             iii

Dedication                                                                                                                                iv

Acknowledgement                                                                                                                   v

Abstract                                                                                                                                    vi

Table of contents                                                                                                                      vii

List of tables                                                                                                                             ix

 

CHAPTER ONE: INTRODUCTION

1.1     General Background                                                                                                          1

1.2     Phytochemicals                                                                                                                  2

1.3     Antibiotics                                                                                                                          2

1.3.1  Penicillins                                                                                                                           2

1.3.2  Cephalosporins                                                                                                                   3

1.3.3  Tetracyclines                                                                                                                       4

1.4     Antimicrobial Assay                                                                                                           5

1.5     Antioxidants                                                                                                                        5

1.5.1  Antioxidant Assays                                                                                                             6

1.6     Botanical Profiles of the Plants                                                                                           6

1.7     Ethnomedicinal Uses of the Plants                                                                                      8

1.8     Objectives of the Study                                                                                                       8

1.9     Scope of the Study                                                                                                              9

1.10  Significance of the Study                                                                                                     9

 

CHAPTER TWO: LITERATURE REVIEW

2.0     General Background                                                                                                          10

2.1     Classes of Phytochemicals                                                                                                11

2.1.1  Alkaloids                                                                                                                           11

2.1.2  Terpenoids                                                                                                                         12

2.1.3  Tannins                                                                                                                              13

2.1.4  Saponins                                                                                                                            13

2.1.5  Flavonoids                                                                                                                         14

2.1.6  Steroids                                                                                                                              15

2.1.7  Essential Oils                                                                                                                    16

2.1.8  Phenolics                                                                                                                           16

2.2     Review of Previous Works on Plants and Phytochemicals                                               17

 

CHAPTER THREE: EXPERIMENTAL

3.1     Sample Collection                                                                                                             23

3.2     Chemicals and Reagents                                                                                                   23

3.3     Apparatus and Equipment used                                                                                        24

3.4     Extraction of the Phytochemicals                                                                                     24

3.5     Identification of the Phytochemicals                                                                                25

3.6     Quantification of the Phytochemicals                                                                              26

3.7     Antioxidant Assay                                                                                                            31

3.8     Antimicrobial Assay of Extracts                                                                                      32

3.8.1  Preparation of Turbidity Standard                                                                                    33

3.8.2  Preparation of Inoculum                                                                                                   33

3.8.3  Inoculation Procedure                                                                                                      34

3.9     Data Analysis, Results and Interpretation                                                                        35

 

CHAPTER FOUR: RESULTS, DISCUSSIONS AND CONCLUSION

4.1     Results of Phytochemical Analysis                                                                                  36

4.1.1  Percentage Yield of the Various Phytochemicals                                                          36

4.1.2  Qualitative Phytochemical Analysis of Various Extracts of Dennettia

          Tripetala and Milicia Excelsa                                                                                        37

4.1.3  Quantitative Analysis of the Phytochemicals                                                                39

4.1.4  Statistical Correlation of the Phytochemicals                                                                41

4.1.5  Results of Antioxidant Analysis                                                                                    44

4.1.5.1  Antioxidant Assay of the Various Extracts of Dennettia Tripetala                            44

4.1.5.2  Antioxidant Assay of the Various Extracts of Milicia Excelsa                                   45

4.1.6     IC50 Values for the Various Extracts                                                                           58

4.1.7     Results of Antimicrobial Analysis                                                                               61

4.1.7.1  Antimicrobial Activities of the Extracts of the Root of Dennettia Tripetala              61

4.1.7.2  Antimicrobial Activities of the Extracts of the Root of Milicia Excelsa                     63

4.2        Discussions                                                                                                                   69

4.3        Conclusion                                                                                                                    76

References                                                                                                                    77

Appendix                                                                                                                      92

 

LIST OF TABLES

4.1        Percentage Yield of the Various Phytochemicals                                                        36

4.2        Phytochemical Analysis of the Various Extracts of Dennettia Tripetala                    37

4.3        Phytochemical Analysis of the Various Extracts of Milicia Excelsa                           38

4.4        Quantitative estimation (g/100 g) of alkaloids, flavonoids, phenols,

saponins, steroids, tannins and glycosides in the roots of Denettia

              tripetala and Milicia excelsa.                                                                                       39

4.5        Correlation Matrix of the Different Phytochemicals in the Roots of

             Dennettia Tripetala                                                                                                       41

4.6        Correlation Matrix of the Different Phytochemicals in the Roots of

             Milicia Excelsa                                                                                                             42

4.7        DPPH Radical-Scavenging Activity (% inhibition) of Various Extracts

of Dennettia Tripetala                                                                                                  44

4.8        DPPH Radical-Scavenging Activity (% inhibition) of Various Extracts

of Milicia Excelsa                                                                                                         45

4.9       DPPH Radical-Scavenging Activity (% inhibition) of Ascorbic Acid Standard           46

4.10      IC50 Values for Various Extracts of the Root of Dennettia Tripetala                           58

4.11      IC50 Values for Various Extracts of the Root of Milicia Excelsa                                  59

4.12      Inhibition Zone Diameter (IZD) of ethanolic extract of the root of

             Dennettia tripetala against tested organisms                                                                 61

4.13      Inhibition Zone Diameter (IZD) of butanolic extract of the root of

             Dennettia tripetala against tested organisms                                                                 62

4.14      Inhibition Zone Diameter (IZD) of butanolic extract of the root of

             Milicia Excelsa against tested organisms                                                                       63

 

CHAPTER ONE

 INTRODUCTION

1.1 GENERAL BACKGROUND

Plants and plant parts are a known source of herbal medicine and natural health-enhancing products for many centuries. Various plant parts such as leaves, fruits, seeds, bark, flowers, rhizomes and roots have at one time or the other been utilized for medicinal purposes. It is estimated that about 75% of useful bioactive plant-derived pharmaceuticals used globally are discovered by systematic investigation of leads from traditional medicines1.The search for antimicrobial agents have over the years led researchers to in-depth study and analysis of various plants and their parts2, 3.

Over the years, infections caused by strains of bacteria that are resistant to orthodox drugs, also called multi-drug resistant (MDR) bacteria, have either found cure or control by the use of bioactive compounds isolated from plants. These bioactive compounds are known as phytochemicals. They can help prevent the spread of or totally eliminate infections. These phytochemicals can either be used alone as antimicrobial agents or in combination with commercially available antibiotics asstudies have shown that a higher activity against microorganisms can be achieved by combining certain phytochemicals with commercially available antibiotics4.For example, Pseudomonas aeruginosa, a microorganism which has exhibited resistance to 19 different antibiotics was observed for synergistic effects when phytochemical extracts from clove, jambolan, pomegranate and thyme were used together with known antibiotics. Results showed that bacterial growth was inhibited at phytochemical concentrations of 50µg/mL even to as low as 10µg/mL and, interestingly also, for antibiotics that previously did not show any activity by themselves against the microorganism5.

1.2 PHYTOCHEMICALS

 

payment

PHYSICOCHEMICAL AND BACTERIOLOGICAL ANALYSES OF BOREHOLE WATERS IN ANINRI, AWGU AND OJI RIVER LOCAL GOVERNMENT AREAS OF ENUGU STATE, NIGERIA

ABSTRACT

Physicochemical and bacteriological analyses of borehole water samples were randomly collected from ten boreholes which supply drinking water to various communities of Aninri, Awgu and Oji River Local Government Areas of Enugu, Nigeria. The boreholes were sampled in both dry and rainy seasons. The following physicochemical parameters: pH, temperature, colour, electrical conductivity, turbidity, total dissolved solids, hardness, calcium, magnesium, sodium, potassium, alkalinity, acidity, lead, copper, cadmium and iron were determined using standard methods. E. coli count was determined by membrane lauryl sulphate broth method. Results of physicochemical tests were in compliance with WHO guideline values, except in the cases of sulphate level of 1,670 mg/L in water sample from Mpu in Aninri L.G.A., high chloride levels in samples from Ndeaboh and Mpu with values of 18,088 and 1,095 mg/L respectively. Similarly, sodium was also very high in the two boreholes, 5,625 and 8,500 mg/L. The water samples showed acid pH particularly in Oji River with values ranging from 4.30 to 6.30. Most of the water samples were soft waters, except samples from Ndeaboh, Mpu and Mgbowo with hardness values of 6,250, 6,250 and 840 mg/L respectively. Trace metal concentrations were below WHO guideline values, except samples from Mgbowo and Nnenwe with iron values of 4.54 and 3.13 mg/L. E. coli was isolated in two boreholes located in unkept surroundings in Oduma and Agbogugu with E. coli counts of 7 and 108 cfu/100 mL respectively. Generally, the borehole waters are considered safe for drinking except these ones polluted with E. coli and sodium chloride. The effects of unsafe drinking water are discussed, with recommendations to the Authorities regarding the safety measures to be applied.

 

CHAPTER ONE

1.0 INTRODUCTION

Water is one of the earth’s most precious resources. Water is often referred to as a universal solvent because it dissolves many minerals. It can exist in three states as liquid, gas (at 100 oC) and solid (at freezing temperature of < 4 oC). Water is fundamentally important to all plants, animals including man1. Without it, there is no life. Good drinking water is not a luxury but one of the most essential amenities of life. Although water is essential for human survival, many are denied access to sufficient potable water supply and sufficient water to maintain basic hygiene. Globally, over one billion people lack access to clean safe water2,3,4. The majority of these people are in Asia (20%) and sub-Sahara Africa (42%). Further, about 2.4 billion people lack adequate sanitation worldwide 5.

It is estimated that > 80% of ill health in developing countries are water and sanitation-related6. Thus, lack of safe drinking water supply and poor hygienic practices due to lack of water are associated with high morbidity and mortality from excreta-related diseases.

Consequently, water-borne pathogens infect around 250 million people each year resulting in 10 to 20 million deaths world-wide5. An estimated 80% of all child deaths under the age of five years in developing countries result from diarrhoea diseases7,8.

Lack of safe drinking water and inadequate sanitation measures could also lead to a number of diseases such as dysentery, cholera and typhoid9,10. Against this backdrop, the supply of safe drinking water to all has been at the front burner at the United Nations Millennium Development Goals (MDGs) to reduce poverty and promote sustainable development worldwide especially in developing countries. Her target for water, is to halve by 2015, the proportion of people without sustainable access to safe drinking water and basic sanitation. However, it is envisaged that this target may not be easy in developing countries because of (a) high population growth, (b) conflict and political instability and (c) low priority given to water and sanitation programmes in developing countries.

 

1.1 Ground Water as Source of Portable Water

 

payment

 

PHYSICO-CHEMICAL STUDIES OF SOIL AND GROUNDWATER AROUND A MUNICIPAL SOLID WASTE DUMPSITE IN GOMBE METROPOLIS

CHAPTER ONE

INTRODUCTION

1.1 General introduction

Rapid increase in population and change in life style in Nigeria have resulted in a dramatic increase in the generation of municipal solid waste (MSW). It includes domestic as well as commercial waste that accounts for a relatively small part of the total solid waste stream in developed countries. Accumulation of a large amount of waste may create several problems to inhabiting populations. Population growth has been contributing to increase in the quality and variety of waste. Collection, transportation and handling of the waste if not properly dealt with, can create a number of problems, many of which are related to human health and environment1,2. Municipal solid waste management is an important part of the urban infrastructure that ensures the protection of environment and human health3,4. The accelerated growth of urban population with unplanned urbanization, increasing economic activities and lack of training in modern solid waste management practices in developing countries complicates the efforts to improve solid waste services5.

However, the unsettling problem is that dumping the waste on soil is one means which the soil quality is degraded.  The polluted soil affects human health through direct human contact or inhalation of the polluted airborne dust and the consumption of the garden vegetables grown on abandoned dumpsites or around active dumpsites6. Solid waste management has become a global problem especially in the developing countries of the world. In Nigeria, for instance it is not unusual to see heaps of garbage in the major cities littering the streets, dumped in drains, vacant plots, and water bodies, and this has in many cases resulted in spread of communicable diseases7. The situation appears to continue unabated due largely to the factors of urbanization, population growth, improved life style and insufficient funds to properly manage solid waste7. Improper management of solid waste areas has resulted in serious ecological, environmental and health problems. Such practices contribute to widespread environmental pollution as well as spread of diseases8. Solid waste disposal methods are a major public concern. Majority of the municipal solid waste disposal sites in Nigeria are still open dumps. Solid waste disposal by landfill poses a threat to groundwater and surface water quality through the formation of polluting liquids known as leachate9.

Leachate generally comes into existence during dissolution in the landfill. The environments can be polluted by the leachate, which occurs at the end of decayed solid waste, mixed with precipitates of surface water. As a result, surface water collection system (rivers, creeks, lakes), subsurface collection system (groundwater reservoirs) and solid system (different soil layers) have been seriously polluted by this leachate9. Landfills are one of the sources of groundwater and soil pollution due to the production of leachate and transportation of the contamination to farther points in the ecosystem8. The contaminations of soil, water and air with heavy metals even at low concentrations are known to have potential impact on environment and human health. These metals also pose a long-term risk to groundwater and ecosystem in general10,11. The WHO, had confirmed the effects of lead intake to include, abortion, infant mortality, malformation of foetus, genetic mutation, retarded growth, intoxication, depression of respiration and chromosomal aberrations. Based on these, researchers postulated ways of controlling the generation of wastes and effects on the environment12.

Environmental monitoring refers to the set of activities that provide chemical, physical, geological, biological and environmental, social or health data required by environmental managers13. Environmental monitoring involves the systematic collection of data to determine: The actual environmental effects of a contaminant. The compliance of contaminant with regulatory standards; or the degree of implementation and success of environmental protection measures when successfully integrated with the environmental system for the project, environmental monitoring can provide valuable feedback about the effectiveness of environmental protection measures and in turn monitoring may be related to the post project evaluation12,13.

Monitoring of soil quality indicators over time identifies changes or trends in the functional status or quality of the soil. Monitoring can be used to determine the success of management practices or the need for additional management changes or adjustments14,15. In Nigeria, agencies like the Federal Environmental Protection Agency (FEPA), Ministry of Environment, and Environmental Sanitation Authorities and even local authorities are responsible for planning a defined line of action for disposal and management of waste generated on daily basis in our society. Gombe States Environmental Protection Agency (GOSEPA) is not an exception. The report that refuse dumps have caused traffic delays in some strategic parts of our urban centre’s is an example of poor management of refuse dumps in Nigeria towns and cities16.

The residents of the present study area use borehole water, which is located close to the dumpsite for drinking and other domestics activities and they also use the soil around the dumpsite is used for farming activities. It is necessary to periodically examine wastes and some pollutants effect on soil and groundwater through soil and water analysis. This will go a long way in providing information needed for the development of techniques for tackling the problem of soil and groundwater pollution and effect of municipal solid wastes on the environment through proper disposal/management strategies.

 

1.2 Statement of the Problem

Humans and other living organisms depend on a healthy environment for good health. The dumpsite examined is situated very close to residential areas. The residential areas have borehole water, and a stream is located close to the dumpsite and used by residents as drinking water and for other domestic activities. Soil around the dumpsite is used for farming activities. Rapid population growth and industrialization, coupled with indiscriminate dumping of solid wastes at the site, with little or no organized solid waste management plans have contributed to increased volume of solid wastes at the dumpsite in an alarming rate. The different wastes at the dumpsite possess different physical, chemical and biochemical properties. The waste water produced from the decomposed wastes materials when it rains, may drain into the nearby surface stream and leach into the sub-surface soil and then into the groundwater aquifers, thereby contaminating the groundwater and soil around the dumpsite. The soil texture around the dumpsite and even outside the dumpsite show very high percentage coarse sand which is highly conducive for leachate transport. In order to determine the quality of the groundwater and soil around the dumpsite, it is necessary to study the chemical constituent of the groundwater and soil samples around the dumpsite. The results of this finding are expected to reveal the present quality of the groundwater and soil around the dumpsite.

1.3 Aim and Objectives of Study

 

payment

 

ORGANOCHLORINE PESTICIDES RESIDUE IN COCOA BEANS (Theobroma cacao) AND SOILS OF COCOA PLANTATIONS IN ONDO STATE, NIGERIA

CHAPTER ONE

1.0       INTRODUCTION

Cocoa is an important tropical tree crop which does not only provide farmers with much desired income to meet their basic family needs1 but also serves as aforeign exchange earner for many West African countries like Nigeria, Ghana, Côte d’Ivoire, Cameroon and  Togo.Its botanical name, Theobroma Cacao, given by Swedish natural scientist Carl Von Linne denotes its rich taste and high nutritional value which make it irresistible to both young and adult especially when processed into diverse products such as chocolate, sweet, cocoa drink, cocoa biscuit, cocoa bread, cocoa cake, cocoa flakes, cocoa popcorn, cocoa jam, cocoa jelly, cocoa cream, cocoa wine and spirit, etc.2-4

Cocoa was believed to have originated in the hot, humid region near the source of the River Amazon in South Africa and introduced into Nigeria in 1874.1,5In Nigeria, Cocoa is grown mostly in Southern States such as Ondo, Oyo, Ogun and Osun. It is a tropical lowland crop which flourishes best where the annual rainfall is at least 1140mm with mean temperature below 170C. It requires shade to reduce moisture evaporation especially at the nursery and the early stages of its establishment in the field. It also requires a deep, fertile and well aerated loamy soil which must beloose and friable. The cocoa plant when mature reaches a height of 7.5 to 10.5m.6

Before 1960, exportation of cocoa accounted mainly for the agricultural export, which made over 80% of the Gross National Product (GNP) of the Nigerian economy.7This showed that cocoa was the chief source of foreign exchange earnings for Nigeria before the discovery and exploration of crude oil. Despite the oil boom experienced in Nigeria, cocoa still serves as the major agricultural export crop and accounted for about 38% of agricultural export in 1997.8Being an important agricultural produce, cocoa provides employment for the farmers in the remote villages and millions of individuals all over the world involved in its processing, marketing and distribution. It is imperative to note that large scale production of cocoa can solve the problems of unemployment in Nigeria. This is because the world demand for cocoa and its derived products is ever increasing and remains insatiable. Eighty-five percent (85%) of the cocoa demand of the European Nations is from West Africa where Nigeria is one of the major exporters5. This showed that the final destination of West African cocoa is Europe.

Although, the cocoa producing Nations in West Africa derive revenue from the export of cocoa to Europe, much more revenue could be derived if the exported cocoa is being processed within the West African region and the finished products is exported for the consumption of the European nations after the satisfaction of the local demands. This could only be achieved if laws are enacted and necessary provisions are made to provide a very conducive environment for the farmers and the local processing industries to strive.However, the discovery of abundant natural resources, such as crude oil in Nigeria, gold in Ghana, probably led to the reduction in effort of most African Governments to make available these required provisions. Consequently, cocoa farming is now left mostly to smallholder farmers (with farm size less than 5 hectares) who rely on the crop as the primary source of income.8 Many of these farmers are geographically isolated, illiterate, poorly informed and have very limited resources for proper crop management. This development has caused a sharp decline in cocoa production as many of the farmers still adopt the traditional methods of farming which is very inefficient and pose high risk to the farmers8.

Unfortunately, the enormous effort of these farmers at sustaining production under high risk conditions was not most often reflected in their output as pests and diseases largely contributed to decline in cocoa production.9In Nigeria, decline in cocoa production started in 1971 and 1972 with yield of 255,000 and 241,000 metric tonnes respectively5. The lowest yield in the 70’s was recorded in 1978 with output of 137,000 metric tonnes5. Yields declined further from a peak of about 350,000 metric tonnes in the mid 80’s to about 58,700 metric tonnes in 19865. According to THISDAYLIVE Newspaper report issued on 21st January, 2014, the cocoa production in Nigeria was 250, 000 metric tonnes in 2011, 300, 000 metric tonnes in 2012, and 350, 000 metric tonnes in 2013. This showed an annual increase in production by 50, 000 metric tonnes but when compared to the annual cocoa production from other West African countries in the same period (Ghana cocoa production was between 850, 000 – 1, 000, 000 metric tonne per annual and Cote d’Ivoire cocoa production was in the range 1.2 – 1.4 million metric tonnes per annual), it would be obvious that the growth rate was not only insignificant but also the annual output was too small for the most populated black Nation (Nigeria) that is expected to champion the course of self sustenance in food production in Africa.

Major contributors to this decline were pests as 25-30% loss in yield of cocoa was attributed to the cocoa mired, Sahlbergella singularis while about 17% was lost through the feeding of the cocoa pod borer Characoma strictigrapta10, 11. The collective efforts of minor pests (such as the shield bug, Bathycoelia thalassina, the pod miner, Mamara species, the root-feeding termites, Macrotermes bellicosus,Mesohomotoma tessmanniand the cacao thrips, Selenothrips rubrocinctus)could become significant especially under suitable conditions in young cocoa or ageing cocoa plantations.

It is important to note that several concerted research efforts have been made to develop various control techniques (such as cultural, biological and chemical) which could be adopted for integrated management of the major and minor pests of cocoa in Nigeria. It is however quite unfortunate to note that many of the findings of such research hardly reached the local farmers and when they did eventually, the inability of the farmers to read and write often hindered the proper interpretation of those findings. Despite the various mechanisms developed for pest management, the farmers rely greatly on the use of pesticides (chemical control technique) because it provides immediate and quicker remedy in the periods of serious pest outbreaks.11

There are over seven hundred (700) chemicals in use as pesticides, which are formulated into about thirty-five thousand products classified as insecticides, herbicides, fungicides and rodenticides.12Although, pesticides are known to be very efficient in pest control, reliance and prolonged application of thesesynthetic chemicals had given rise to numerous problems which affected the food chain and posed negative impact on biological diversity. It has been established that pesticides application could lead to serious health hazard ( such as epilepsy, stroke, respiratory disorders, leukemia, convulsion, brain and liver tumors ) and environmental pollution as it is often manifested in the disturbance of the ecosystem,which include destruction of some natural vegetation, pollution of the important water bodies (ground water, river water, drinking water), soil and air as well as reduction and extinction of some aquatic species and wildlife population.13-15

In Nigeria, cocoa farmers use different insecticide formulations including the very notorious organochlorine types. Due to their bioaccumulation throughout the food chain and prolonged persistence in the environment coupled with numerous associated health risk, food and environmental regulatory bodies in many developed and developing nations,including National Agency for Food and Drug Administration and Control (NAFDAC) in Nigeria, place ban on the use of most pesticides especially those with organochlorine formulations in line with the new European Union Legislation on pesticide use.16 Despite, the ban on these chemicals, the hazards associated with them still remain for long period as many of them possess extended half-life especially the organochlorines which are very stable and persist for a long period of time.The problem is further complicated as these compounds have many derivatives which are very soluble in body fat and can move with relative ease through the food chains.

It is therefore very expedient to provide adequate quantitative and qualitative information on these banned pesticidesand their derivatives in soil, farm produce (e.g. cocoa) and water. This is to assist; the farmers (who use these pesticides), government (in the formulation of policy)and the general public (to make the consuming populace aware of the associated danger inherent in consumption of farm produce and water contaminated withpesticides). These can only be achieved through concerted research effort tailored and targeted towards acquiring this much important information.

 

payment

 

 

MODIFICATION OF COCONUT SHELL ACTIVATED CARBON WITH AN AZO LIGAND: 1, 2– DIHYDRO-1, 5- DIMETHYL-2 PHENYL-4- (E)–(2,3,4-TRIHYDROPHENYL)-3H-PYRAZOL-3-ONE (DDPTP) AND ITS POTENTIALS FOR THE REMOVAL OF Cd2+, Pb2+ and Ni2+ FROM POLLUTED WATER

ABSTRACT

Modification of coconut (Cocos nucicera L.) shell activated carbon with an Azo ligand: 1, 2– dihydro-1,5-dimethyl-2-phenyl-4-(E)–(2,3,4-trihydrophenyl)-3H-pyrazol-3-one (DDPTP) and its potentials for the removal of Cd2+, Pb2+ and Ni2+ from polluted water samples were studied. It was activated chemically using CaCO3 as the activating agent. Proximate analysis on the coconut shell showed 8.7 % moisture content, 10.4 % volatile matter, 3.2 % ash content and 77.7 % fixed carbon. The developed adsorbent has bulk density of 0.46 g/cm3, pore volume of 8.0 x 10-3 cm3 and the conductivity was 37.9 µS/cm. Fourier Transform Infrared (FTIR) analysis showed that hydroxyl, carbonyl, amino and azo groups are present on the surface of the adsorbent. Scanning Electron Microscope (SEM) showed the micro-pores in the Modified Coconut Shell Activated Carbon (MCSAC) while Energy Dispersive X-ray Spectrum exposed carbon as the major quantitative element with 57 %. Batch adsorption was carried out and the results obtained showed that, MCSAC adsorbed Pb2+ (98 %), Cd2+ (80 %) and Ni2+ (92.2 %) ions more than un-modified coconut shell activated carbon which adsorbed Pb2+ (79 %), Cd2+ (60.2 %) and Ni2+ (73.6 %) ions from aqueous solutions. The quantity of the metal ions adsorbed increased with increase in initial concentrations, contact time, temperature of carbonization, the degree of treatment of adsorbent and pH for each metal. The percentage removal decreased with increase in particle sizes of the adsorbent. It also increased initially with increase in ligand amount but later decreased. Competitive adsorption of Pb2+, Cd2+ and Ni2+ on MCSAC from their mixed solution showed that the percentage removal of Ni2+ was highest with 80.35 % followed by Pb2+, 71.05 % and Cd2+, 45.10 %. The analysis of adsorption isotherm showed that, adsorption of Ni2+ followed Langmuir isotherm than Cd2+ and Pb2+; Ni2+ and Cd2+ followed Freunlich isotherm than Pb2+; Ni2+ and Pb2+ followed Temkin isotherm than Cd2+. Kinetic studies showed that the sorption of the metal ions can also be described by pseudo-first-order (Pb2+ and Ni2+), pseudo-second-order (Cd2+ and Ni2+) and intra-particle diffusion models for the three metals.

 

CHAPTER ONE

1.0     Introduction

1.1     Background of the Study

The presence of trace heavy metals in natural water has aroused the interest of many Nigerian scientists as a result of their environmental effects on the health of both plants and animals. More so, concerns about environmental protection has increased due to the technology development which keeps on changing, producing industrial product, as well as waste. Manufacturing industries have played an important role for economic growth in major countries. This sector provides services and product for better way and quality of life. However, rapid change in industrialization produces vast amount of waste and will cause harm and deterioration of the environment and ecosystem if improperly managed. Pollutants from textiles industry was declared as one of the major sources of wastewater in Asian country1 as it is considered as possible carcinogenic or mutagen. Apart from that, heavy metals such as cadmium, chromium, lead, copper, manganese, zinc as well as mercury and nickel are widely discharged in the wastewater from industries and are very toxic and harmful to living organisms by lowering the reproductive success, preventing proper growth and even causing death2. Some of the heavy metals are important for our body requirement; however exceeding the tolerance limit may create harm to body functions.

The most toxic heavy metals are Cd, Pb and Hg ions due to their high attraction for sulphur which will disturb enzyme function by forming bon d with sulphur. The ions will hinder the transport process through the cell wall, thereby disturbing the cell function. Other pollutants from the industries are phenol; from refineries, petrochemical wastewater, pulp mills and coal mines. Presence of phenols in water bodies caused carbolic odor to receiving water bodies, thus causing toxic effects on aquatic flora and fauna3. Apart from that it is also toxic to humans and affects several biochemical functions4.

Unlike organic pollutants, heavy metals do not biodegrade and thus, pose a different kind of challenge for remediation. To alleviate the problem of water pollution by heavy metals, various methods have been used to remove them from waste water such as chemical precipitation, coagulation, floatation, adsorption, ion exchange, reverse osmosis and electrodialysis5-7. The production of the sludge in the precipitation methods poses challenges in handling treatment and hand filling of the solid sludge. Ion exchange usually requires a high – capital investment for the equipment as well as high operational cost. Electrolysis allows the removal of metal ions with the advantage that there is no need for additional chemicals and also there is no sludge generation. However, it is inefficient at a low metal concentration. Membrane processes such as reverse osmosis and electrodialysis tend to suffer from the in-stability of the membranes in salty or acidic conditions and fouling by inorganic and organic substances present in waste water8. Most of these techniques have some pretreatments and additional treatments. In addition, some of them are less effective and require high cost9.

It was only in the 1990s that a new scientific area, biosorption was developed that could help in the recovery of heavy metals. The first reports described how abundant biological materials could be used to remove, at very low cost, even small amounts of toxic heavy metals from industrial effluents9-11. Metal-sequestering properties of non-viable microbial biomass provide a basis for the removal of heavy metals when they occur at low concentrations9. Therefore, many researchers have applied regenerated wastes to treat heavy metals from aqueous solutions.

The main objective of the method is to treat the wastewater before discharging to water source, thus decreasing the threat and deterioration to the environment and promising better sustainability of the environment. There are many technologies that have been developed for purification and treatment of waste water including chemical precipitation, solvent extraction, oxidation, reduction, dialysis/electro dialysis, electrolytic extraction, reverse osmosis, ion-exchange, evaporation, cementation, dilution, adsorption, filtration, floatation, air stripping, steam stripping, flocculation, sedimentation and soil flushing/washing chelation12. The selection technologies must be analyzed accordingly based on several factors such as available space for construction of treatment facilities, ability of process equipment, limitation of waste disposal, desired final water quality and cost of operation. Mostly, all the technologies listed above are less likely to be selected because they required large financial input and their applications are limited due to the associated cost factors. Adsorption process is found to be the most suitable technique to remove pollutants from wastewater. It is mostly preferred due to its convenience, ease of operation and simplicity of design. Apart from removing many types of pollutants, it also has wide application in water pollution control. Activated carbon (AC) is widely used as absorbent due to its high surface area and pore volume as well as inert properties. However, conventional AC is expensive due to the depletion of coal-based source and especially for producing high quality AC13.

To counter the high cost of AC, low cost precursors have been of high interest for researchers to replace the conventional AC. The factors affecting substitution of raw material are high carbon content, low inorganic content, high density and sufficient volatile content, stability of supply in the countries, potential extent of activation and inexpensive material6. The AC is mainly comprised of carbon with large surface area, large pore volume and porosity where the adsorptions take place.

There are some reviews reporting the use of coconut and palm shell for the production of AC14; however such studies are restricted to either type of wastes, preparation procedures, or specific aqueous-phase applications. But, due to the abundant source of precursors, with high volatile, carbon contents, and hardness; coconut shells are an excellent raw material source to produce activated carbon suitable to replace conventional AC14. Moreover, this can be said to be, “substitution of waste to wealth”. The adsorption capacity of the adsorbent could be improved by its modification. This is because; the functional groups on the surface of the AC could be improved by modification with a ligand that has electron donating groups like hydroxyl group, amide group, etc.

It is the aim of the research to adsorb Pd2+, Cd2+ and Ni2+ from waste water sample on locally prepared activated charcoal from coconut shell modified with an azo ligand; 1,2 –dihydro -1,5-dimethyl-2-phenyl-4-(E)- (2,3,4-trihydrophenyl)-3H-pyrazol-3-one (DDPTP).

 

1.2.    Statement of the Problem

 

payment