Laboratory Techniques in Electroanalytical Chemistry Second Edition, Revised and Expanded

edited by

Peter I Kissinger Purdue University and Bioanalytical Systems, Inc. West Lafayette, Indiana

William R. Heineman University of Cincinnati Cincinnati, Ohio

M A R C E L m MARCEL DEKKER, INC. NEW YORK • BASEL

» S H E «

Contents

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Preface Contributors

An Overview Peter T. Kissinger

I. Some Philosophy II. Progress and Prognosis

III. So Much Nomenclature, So Much Jargon Bibliography

Fundamental Concepts of Analytical Electrochemistry Peter T. Kissinger, Carl R. Preddy, Ronald E. Shoup, and William R. Heineman

I. Introduction II. Mass Transport: Linear Diffusion

III. The Charged Interphase IV. The Nernst Equation and Electrochemical Reversibility V. Coupled Chemical Reactions and Chemical Reversibility

VI. Liquid-Solid Adsorption VII. Conclusion

References

Large-Amplitude Controlled-Potential Techniques William R. Heineman and Peter T. Kissinger

I. Introduction II. Potential-Step Techniques in Stationary Solution

III. Potential-Scan Techniques in Stationary Solution IV. Controlled-Potential Techniques in Flowing Solution

References

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Contents

4 Large-Amplitude Controlled-Current Techniques 127 William R. Heineman and Peter T. Kissinger I. Controlled-Current Techniques in Stationary Solution 127

II. Controlled-Current Techniques in Flowing Solution 139 References 139

5 Small-Amplitude Controlled-Potential Techniques 141 Peter T. Kissinger and Thomas H. Ridgway

I. Introduction 141 II. Faradaic Impedance 148

III. Sinusoidal Alternating-Current Voltammetry 150 IV. Cyclic Alternating-Current Voltammetry 152 V. Tensammetry 153

VI. Step-Based Methods 154 VII. Staircase Voltammetry 155

VIII. Differential Pulse Methods 156 IX. Square-Wave Methods 158 X. Differential "Normal Pulse" Voltammetry 159

XI. Conclusion 161 References 163

6 Introduction to Analog Instrumentation 165 Peter T. Kissinger

I. Classical Controlled-Potential Instrumentation 165 II. Controlled-Potential Instrumentation Based on Operational

Amplifiers 172 III. Classical Controlled-Current Instrumentation 187 IV. Controlled-Current Instrumentation Based on Operational

Amplifiers 188 V. Microprocessor-Based Electrochemical Instrumentation 189

VI. Conclusion 194 Reference 194

7 Overcoming Solution Resistance with Stability and Grace in Potentiostatic Circuits 195 David K. Roe

I. Introduction 195 II. Input-Output Relations of Cells and Potentiostats 199

III. Stability of Potentiostat-Cell Circuits and the Role of Ru 205 IV. Compensation for iRu by Positive Feedback 217 V. Achieving Stability Through Gain-Frequency Shaping 222

VI. Real Systems 231 Appendix 232 Bibliography 234

Contents

8 Conductivity and Conductometry F. James Holler and Christie G. Enke

I. Some Basic Relationships II. DC Contact Measurement of Conductance

III. Capacitive Contact Measurement of Conductance References

9 Electrochemical Cells Fred M. Hawkridge

I. Design Concepts II. Stationary-Solution Experiments

III. Convected-Solution Experiments IV. Thin-Layer Cell Design V. Cells for Spectroelectrochemistry

References 10 Carbon Electrodes

Richard L. McCreery and Kristin K. Cline I. Introduction

II. Performance Criteria III. Carbon Electrode Materials Properties IV. Common Carbon Electrode Materials V. Selection of Carbon Electrodes for Analytical Applications

References

11 Film Electrodes James L. Anderson and Nicholas Winograd

I. Introduction II. Applications of Thin-Film Electrodes

III. Properties of Film Electrodes IV. Metal Film Electrodes V. Carbon Film Electrodes

VI. Semiconductor Film Electrodes VII. Techniques of Cell Design Based on Film Electrodes

VIII. Prospects for Disposable, Integrated Sensor Systems References

12 Microelectrodes Adrian C. Michael and R. Mark Wightman

I. Introduction II. Construction of Microelectrodes

III. Diffusion at Microelectrodes IV. High-Speed Cyclic Voltammetry V. Ohmic Drop at Microelectrodes

237

238 Z44 251 264 лЛЗ 1

267

276 280 283 289 293

293 one 299 304 327 330 333

333 334 337 351 354 357 359 361 362 367

367 368 372 381 385

X Contents

VI. Very Small Electrodes 396 VII. Conclusions 398

References 399

13 Chemically Modified Electrodes 403 Charles R. Martin and Colby A. Foss, Jr.

I. Introduction 404 II. Methods for Preparing Chemically Modified Electrodes 404

III. Electrochemistry at Chemically Modified Electrodes 412 IV. Characterization and Analysis of Chemically Modified

Electrodes 419 V. Applications of Chemically Modified Electrodes 431

VI. Conclusions 438 References 439

14 Mercury Electrodes 443 Zbigniew Galus

I. Introduction 443 II. Dropping Mercury Electrode 444

III. Hanging Mercury Drop Electrode 452 IV. Static Mercury Drop Electrode 456 V. Streaming Mercury Electrodes 457

VI. Mercury Film and Other Types of Mercury Electrodes 461 References 466

15 Solvents and Supporting Electrolytes 469 Albert J. Fry

I. Introduction 469 II. Recommended Solvents and Electrolytes 473

III. Some Other Solvents 474 IV. Solvent- and Electrolyte-Dependent Phenomena 476 V. Experimental Procedures 478

Appendix: Other Literature 482 References 483

16 Electrochemical Studies at Reduced Temperature 487 Dennis H. Evans and Susan A. Lerke

I. Introduction 487 II. Motivations for Variation of the Temperature in

Electrochemical Studies 488 III. Examples of the Study of the Rates of Coupled Chemical

Reactions 492 IV. Practical Aspects of Electrochemical Studies at Low

Temperatures 500 References 509

Contents xi

17 Electroanalytical Chemistry in Molten Salts 511 Charles L. Hussey

I. Introduction 511 II. Molten Salt Systems 513

III. Apparatus and Techniques 523 References 538

18 Vacuum-Line Techniques 543 Vladimir Katovic, Michael A. May, and Csaba P. Keszthelyi

I. Introduction 543 II. Vacuum Line 544

III. Electrochemical Glassware for the Vacuum Line 552 References 565

19 Electrochemistry in the Dry Box 569 Steven N. Frank and Su-Moon Park

I. Introduction 569 II. Choosing an Inert-Atmosphere System 570

III. Experimental Procedures 572 Appendix 580 References 580

20 Digital Simulation of Electrochemical Problems 583 J. T. Malay

I. Introduction 583 II. The Finite Difference Representation of Fick's Laws 584

III. The Model Diffusion Coefficient: Defining At and Ax 586 IV. Establishing Initial and Boundary Conditions 588 V. Dimensionless Parameters 591

VI. A Sample BASIC Program 593 VII. Chronocoulometry 595

VIII. Other Nernstian Electrode Boundary Conditions 599 IX. Homogeneous Kinetics 601 X. Parametric Substitutions 606

XI. Electrogenerated Chemiluminescence 608 XII. Chronopotentiometry 609

XIII. Linear Sweep and Cyclic Voltammetry 611 XIV. Simulation of Rotating Disk Hydrodynamics 613 XV. Simulation of Rotating Ring Disk Behavior 614

XVI. The Steady-State Assumption 616 XVII. Beyond the Basics 619

References 620

xH Contents

21 Evaluation of Mechanisms of Organic Reactions 623 M. Dale Hawley

I. Introduction 623 II. Reduction of p-Chlorobenzonitrile 624

III. Oxidation of Adrenaline 629 IV. Oxidation of a-Tocopherol 633 V. Concluding Remarks 639

References 640

22 Electroorganic Synthesis 641 Eberhard Steckhan

I. What Is Electroorganic Synthesis? 641 II. Advantages and Disadvantages of Electroorganic Reactions 641

III. Technically Interesting Processes 643 IV. Classification of Electroorganic Reactions 647 V. Experimental Factors and Techniques 665

References 677

23 Instructional Examples of Electrode Mechanisms of Transition Metal Complexes 683 William E. Geiger

I. Electrode Mechanisms 683 II. Obtaining High-Quality Data 686

III. Mechanistic Studies 693 IV. Examples of Selected Mechanisms 694 V. Comments on Second-Order Homogeneous Reactions 715

References 717

24 Electrochemical Preconcentration 719 Joseph Wang

I. Why Preconcentration? 719 II. Stripping Analysis 719

III. Electrochemical Preconcentration for Spectroscopic Analysis 734 References 735

25 Controlled-Current Coulometry 739 David J. Curran

I. Introduction 739 II. Coulometric Generation of Reagents 740

III. Coulometric Titrations 750 References 766

Contents xüi

26 Electrochemistry in Pharmaceutical Analysis 769 Marvin A. Brooks and Eric W. Tsai

I. Introduction 769 II. Coulometric Methods 774

III. Voltammetric Methods 782 References 806

27 Electrochemical Detection in Liquid Chromatography and Capillary Electrophoresis 813 Susan M. Lunte, Craig E. Lunte, and Peter T. Kissinger

I. Introduction 813 II. Transducer Design 816

III. Waveforms 832 IV. Applications Review 840 V. Capillary Electrophoresis/Electrochemistry 847

VI. Conclusions 850 VII. Performance Criteria for Electrochemical Detectors 851

References 852

28 Photonic Electrochemistry 855 Andrew B. Bocarsly, Hiroyasu Tachikawa, and Larry R. Faulkner

I. Introduction 855 II. Photoelectrochemistry—Semiconductor/Electrolyte Interfaces 856

III. Photoemission from Metal Electrodes 882 IV. Electrochemical Monitoring of Photolytic Intermediates 884 V. Electrochemiluminescence 887

Appendix: Structures of Cited Molecules 895 References 896

29 Principles and Techniques of Electrochemical-Electron Paramagnetic Resonance Experiments 901 Ira B. Goldberg and Ted M. McKinney

I. Magnetic Resonance in Electrochemical Studies 901 II. Molecular Orbitals in Electrochemistry and EPR 903

III. Principles of EPR 907 IV. EPR Instrumentation 920 V. Experimental Methods of EPR-Electrochemical Studies 927

VI. Selected Applications of EPR and Electrochemical Measurements 943 Appendix I: Selected Bibliography 954 Appendix II: Units 956 References 957

Index 961