Front Cover

Electrochemistry of Dihydroxybenzene Compounds

Copyright Page

Contents

List of Figures

List of Tables

List of Schemes

Acknowledgments

List of Abbreviations and Symbols

1 Introduction

1.1 Nanotechnology and Nanoscience

1.1.1 Type and Properties of Nanostructures

1.1.2 Applications of Nanomaterials

1.2 Carbon-Based Materials

1.2.1 Carbon-Based Materials in Electrochemistry

1.3 The Importance of Electrode Surface in Electrochemistry

1.3.1 Multiwalled Carbon Nanotube

1.3.2 Graphene

1.3.3 Benefits of Applying Carbon Nanotubes (CNTs) and Graphene in Electrochemical Analysis

1.4 Polymer Nanocomposite (PNC) Based on Carbon Nanomaterial Electrode

1.4.1 PNC Based on Multiwalled Carbon Nanotube (MWCNT)

1.4.2 PNC Based on Graphene

1.5 Conductive Polymer

1.5.1 Types of Conducting Polymers

1.5.2 Poly(4-vinylpyridine) (P4VP) as a Conducting Polymer

1.6 Electroorganic Synthesis

1.7 Dihydroxybenzenes and Its Derivatives

1.7.1 Catechol

1.7.2 Hydroquinone

1.8 Electrochemical Synthesis of CT in the Presence of Nucleophile

1.8.1 Thiosemicarbazide

1.9 Methods Used for Determination of Dihydroxybenzene (DHB)

1.9.1 Electrochemical Method

1.10 Electrochemical Sensors for Analysis

1.10.1 CT as a Sensor for Electrochemical Determination

1.10.2 Electrochemical Sensor for Detection of CT and HQ

1.10.2.1 Determination of Catechol

1.10.2.2 Determination of Hydroquinone

1.10.2.3 Simultaneous Determination of CT and HQ on Modified Electrodes

1.11 Application of the Nanocomposite-Modified Electrodes for Pharmaceutical Analysis

1.11.1 Determination of Paracetamol (PCT)

1.11.2 Determination of Acetylsalicylic Acid (ASA)

1.11.3 Determination of Caffeine

1.12 Problem Statement

1.13 Objectives

2 Experimental

2.1 Materials

2.2 Instruments

2.3 Electrochemical Method for Synthesis of Dihydroxybenzenes Derivatives

2.3.1 Preparation of Working Electrode

2.3.2 Electrochemical Study of CT in the Presence of TSC

2.3.3 Electroorganic Synthesis

2.4 Electrochemical Study of Modified Electrodes

2.4.1 Purification and Acetic Functionalization of MWCNTs

2.4.2 Preparation of P4VP/MWCNT-Modified GCE

2.4.3 Graphene Sheets Functionalization

2.4.4 Preparation of P4VP/GR-Modified GCE

2.5 Determination of TSC in Real Samples

2.5.1 Determination of TSC in Water Samples

2.5.2 Determination of TSC in Propranolol Tablets

2.6 Electrochemical Sensor Studies

2.6.1 Electrochemistry Determination of Diphenols

2.6.2 Electrochemistry of PCT

2.6.3 Electrochemistry of Aspirin and Caffeine

2.7 Real Sample Analysis

2.7.1 Determination of Diphenols in Water Samples

2.7.2 Determination of PCT in Formulation Tablets

2.7.3 Determination of PCT in Urine Mid-Samples

2.7.4 Determination of ASA in Formulation Tablets

2.8 Characterization of the Modified Electrodes

2.8.1 Electrochemical Characterization

2.8.2 Morphology Characterization

2.8.2.1 Field Emission Scanning Electron Microscopy (FESEM) Study

2.8.2.2 Transmission Electron Microscopy

3 Results and Discussion

3.1 Cyclic Voltammetric Studies of CT in Absence and Presence of TSC

3.1.1 Effect of pH

3.1.2 Effect of Scan Rate

3.2 Controlled-Potential Bulk Electrolysis for Electroorganic Synthesis of the Product

3.3 Characterization of 6,7-Dihydroxy-1,2-Dihydrobenzo[e] [1,2,4]-Triazine-3(4H)-Thione Compound, 7

3.3.1 Elemental Analysis

3.3.2 FTIR Analysis

3.3.3 1H NMR and 13C NMR Analysis

3.4 Quantification of TSC

3.5 Interference Studies

3.5.1 Effect of Foreign Ions

3.5.2 Effect of Organic Solvents and Some Organic and Inorganic Compounds

3.6 Applications

3.7 Electrochemical Characterization of P4VP/MWCNT–GCE

3.7.1 Surface Morphology Studies

3.7.2 CV Studies

3.7.3 EIS Studies

3.8 Electrochemical Characterization of P4VP/GR–GCE

3.8.1 CV Studies

3.8.2 Surface Morphology Studies

3.8.3 Electrochemical Impedance of P4VP/GR–GCE

3.9 Electrochemistry of HQ and CT on the P4VP/MWCNT–GCE

3.9.1 Effects of Solution pH

3.9.2 Effect of Scan Rate

3.10 Determination of CT and HQ Using DPV

3.11 Application to Real Sample Analysis

3.12 Interference Studies

3.13 Reproducibility and Stability of P4VP/MWCNT–GCE

3.14 Electrochemistry of Diphenols on the P4VP/GR–GCE

3.14.1 Effects of Solution pH

3.14.2 Effect of Scan Rate

3.15 Determination of CT and HQ Using DPV

3.16 Application to Real Sample Analysis

3.17 Interference Studies

3.18 Reproducibility and Stability of P4VP/GR–GCE

3.19 Analysis of Pharmaceutical Sample

3.20 Electrochemical Behavior of PCT

3.20.1 Effects of Solution pH

3.20.2 Effect of Scan Rate

3.21 Determination of PCT by DPV

3.22 Analysis of Real Samples

3.22.1 Determination of PCT in Formulation Tablets

3.22.2 Determination of PCT in Urine Samples

3.23 Reproducibility and Stability of P4VP/MWCNT–GCE

3.24 Interference Studies

3.25 Electrochemical Behavior of PCT on the P4VP/GR–GCE

3.25.1 Effect of Solution pH

3.25.2 Influence of Scan Rate

3.26 Determination of PCT by DPV

3.27 Determination of PCT in Pharmaceutical and Biological Samples

3.27.1 Determination of PCT in Formulation Tablets

3.27.2 Determination of PCT in Urine Samples

3.28 Reproducibility and Stability of P4VP/GR–GCE

3.29 Interference Studies

3.30 CV of ASA at the P4VP/MWCNT–GCE

3.31 CV of Caffeine at the P4VP/MWCNT–GCE

3.31.1 Effects of pH and Scan Rate on the Oxidation of Caffeine

3.32 Determination of ASA and Caffeine Individually

3.33 Analytical Applications

3.34 Simultaneous Determination of PCT, ASA, and Caffeine

3.35 Reproducibility and Stability

4 Conclusion

References

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