Electrochemical Detection in Hplc

by Flanagan, Robert J.; Perrett, David; Whelpton, Robin

• ISBN13: 9780854045327
• ISBN10: 0854045325
• Format: Hardcover
• Copyright: 2005-08-01
• Publisher: Royal Society of Chemistry

Summary

Electrochemical Detection in HPLC: Analysis of Drugs and Poisons is the first monograph devoted to the application of this mode of analysis to the assay of exogenous compounds such as drugs in biological fluids and associated areas. The introductory chapters provide information on basic electrochemistry and HPLC-ED, and on trouble-shooting. The specialized area of thiol analysis is also discussed in detail. Salient practical details of published applications of the technique in analytical toxicology and related areas are provided in a standard format. Alternative techniques are suggested throughout. The emphasis is on the analysis of exogenous compounds, although catecholamines and other endogenous species are discussed in so far as they may be used as drugs. The practical nature of this book will make it useful to professionals working in the field. It will also be of benefit to analysts wishing to use HPLC-ED in the analysis of biological samples for analytes not specifically covered in the volume.

Table of Contents

List of Abbreviations	xi
Chapter 1 General Introduction	1	(5)
1 Introduction	1	(2)
2 HPLC-ED in Analytical Toxicology	3	(2)
References	5	(1)
Chapter 2 Basic Electrochemistry for the Separation Scientist	6	(15)
1 Reversible Electrode Potentials	6	(3)
1.1 Redox Electrodes	7	(2)
2 Theoretical Background Linking Electrochemistry to Electrochemical Detection	9	(2)
3 Reference Electrodes	11	(2)
3.1 Standard Hydrogen Electrode	11	(1)
3.2 Calomel Electrode	11	(1)
3.3 Silver/Silver Chloride Electrode	12	(1)
4 Voltammetry	13	(3)
4.1 Cyclic Voltammetry	13	(2)
4.2 Hydrodynamic Voltammograms	15	(1)
5 Electroactivity of Functional Groups and Compounds	16	(4)
5.1 Electrochemical Behaviour of Some Specific Molecular Types	18	(2)
References	20	(1)
Further Reading	20	(1)
Chapter 3 The Electrochemical Detector	21	(35)
1 Introduction	21	(1)
2 Theoretical Background to ED in Flowing Liquid Streams	21	(2)
3 The Construction of an Electrochemical Detector	23	(7)
3.1 Principles of Electrochemical Measurement	23	(1)
3.2 Electrode Materials	24	(4)
3.3 Electrode Shielding and Grounding	28	(1)
3.4 Flow-Cell Designs	28	(1)
3.5 Chromatographic Factors Affecting Flow-Cell Design	29	(1)
3.6 Circuitry of an Electrochemical Detector	30	(1)
4 Amperometric Detection	30	(4)
4.1 Thin-Layer Cells	30	(1)
4.2 Wall-Jet Cells	31	(1)
4.3 Dropping Mercury Electrodes	32	(1)
4.4 Operation of Amperometric Electrodes	33	(1)
5 Coulometric Detection	34	(7)
5.1 Modes of Operation	37	(4)
6 Pulsed Detection	41	(2)
7 Multiple Detection Systems	43	(3)
7.1 Array Detectors	43	(2)
7.2 Rapid Scanning Detectors	45	(1)
7.3 Use in Series With Other Detectors	45	(1)
8 Micro-Detectors	46	(3)
8.1 Detectors for Capillary Systems	47	(2)
9 Comparative Performance of EC Detectors	49	(1)
References	50	(6)
Chapter 4 Development and Troubleshooting of HPLC-ED Methods	56	(23)
1 System Optimisation	56	(9)
1.1 Hydrodynamic Voltammograms	57	(2)
1.2 Eluent Composition	59	(3)
1.3 Temperature	62	(1)
1.4 Flow-Rate	63	(1)
1.5 Electrode Surface	63	(1)
1.6 Gradient Elution	64	(1)
2 Analyte-Related Variables	65	(7)
2.1 Electrochemical Oxidation	66	(1)
2.2 Electrochemical Reduction	66	(1)
2.3 Common Interferences in Biofluid Analyses	67	(1)
2.4 Sample Preparation and Choice of Internal Standard	68	(1)
2.5 Derivatisation	69	(2)
2.6 Hydrolysis/Photolysis/Enzymic Reactions	71	(1)
3 Maintenance of HPLC-ED Systems	72	(2)
References	74	(5)
Chapter 5 Thiols, Disulfides and Related Compounds	79	(25)
1 Introduction	79	(3)
1.1 Biologically Important Thiols	79	(1)
1.2 Thiol-Containing Drugs	80	(2)
1.3 Biochemical Background to Thiol Analysis	82	(1)
2 Sample Preparation	82	(2)
2.1 Standard Solutions	82	(1)
2.2 Blood and Tissues	83	(1)
2.3 Urine	83	(1)
3 Measurement of Free Thiols using HPLC-ED	84	(1)
4 Electrochemistry of Thiols	84	(1)
5 Electrochemical Detection of Thiols	85	(5)
5.1 Detection at Mercury Electrodes	85	(1)
5.2 Detection at Gold Amalgam Electrodes	86	(2)
5.3 Detection at Other Solid Electrodes	88	(2)
5.4 Formation of Electroactive Derivatives of Thiols	90	(1)
6 The Electrochemistry of Disulfides and Related Compounds	90	(1)
7 The Electrochemical Detection of Disulfides plus Thiols	90	(5)
7.1 Direct Detection of Disulfides	91	(1)
7.2 Indirect Detection of Disulfides	92	(1)
7.3 In-Series Detection of Disulfides	92	(3)
8 Other Electrochemical Methods for Thiols and/or Disulfides	95	(1)
9 Analysis of Selenium-Containing Compounds	96	(1)
10 Conclusions	96	(1)
References	97	(7)
Chapter 6 Applications of HPLC-ED in the Analysis of Drugs	104	(107)
1 Anaesthetics	104	(2)
2 β2-Adrenergic Agonists	106	(5)
3 Anticancer Drugs	111	(9)
3.1 Alkylating Agents	111	(1)
3.2 Antimetabolites	112	(1)
3.3 Cytotoxic Antibiotics	113	(1)
3.4 Photosensitisers	114	(1)
3.5 Podophyllotoxins	115	(2)
3.6 Vinca Alkaloids	117	(1)
3.7 Miscellaneous Anticancer Drugs	118	(2)
4 Anticholinergics	120	(1)
5 Anticholinesterases	121	(2)
6 Antidepressants	123	(4)
7 Antihistamines	127	(1)
8 Anti-infectives	128	(12)
8.1 Aminoglycoside Antibiotics	129	(1)
8.2 Anti-Folate Drugs	129	(1)
8.3 Antifungals	130	(1)
8.4 Antimalarials	131	(4)
8.5 Antiviral Drugs	135	(1)
8.6 Inhibitors of Bacterial Cell Wall Synthesis	136	(1)
8.7 Macrolide Antibiotics	137	(2)
8.8 Miscellaneous Antibiotics	139	(1)
9 Antimigraine Drugs	140	(1)
10 Antiparkinsonian Drugs	141	(2)
11 Antipsychotics	143	(6)
12 Anxiolytics	149	(1)
13 Cannabinoids	150	(2)
14 Cardiovascular Drugs	152	(11)
14.1 β-Adrenoceptor Antagonists	152	(3)
14.2 Calcium Channel Blockers	155	(3)
14.3 Sympathomimetics	158	(2)
14.4 Other Anti-Hypertensive Agents	160	(1)
14.5 Antiarrhythmic Agents	161	(1)
14.6 Angiotensin-Converting Enzyme Inhibitors	162	(1)
15 Diuretics	163	(2)
16 Non-Opioid Analgesic/Antipyretic/Anti-inflammatory Drugs	165	(3)
17 Opioid Agonists and Antagonists	168	(5)
18 Miscellaneous Pharmaceuticals	173	(6)
References	179	(32)
Chapter 7 Applications of HPLC-ED in Toxicology and Related Areas	211	(8)
1 Ammatoxins	211	(1)
2 Aromatic Amines and Nitro-Compounds	211	(1)
3 Algal and Fungal Toxins	212	(1)
4 Pesticides and Related Compounds	213	(2)
5 Veterinary Drug and Other Food Residues	215	(2)
References	217	(2)
Appendix Non-Aqueous Ionic Eluent Systems for Basic Drugs	219	(6)
References	224	(1)
Subject Index	225