LABORATORY TECHNIQUES IN ELECTROANALYTICAL CHEMISTRY Editors PETER T. KISSINGER Purdue Uniuersity and Bioanalytical Systems, Inc. West Lafayette, Indiana WILLIAM R. HEINEMAN Uniuersity of Cincinnati Cincinnati, Ohio MARCEL DEKKER, INC. New York and Basel
Contents Preface 1 An Overview 1 I. Some philosophy 1 II. Progress and prognosis 3 III. So much nomenclature, so much Jargon 5 2 Fundamental Concepts of Analytical Electrochemistry 9, Carl R. Preddy, Ronald E. Shoup, and William R. Heineman I. Introduction 9 II. Linear diffusum 10 III. The charged interphase 25 IV. The Nernst equation and electrochemical reversibility 29 V. Coupled chemical reactions and chemical reversibility 39 VI. Liquid-solid adsorption 43 VII. Conclusion 48 References 49 3 Large-Amplitude Controlled-Potential Techniques 51 William R. Heineman and I. Introduction 52 II. Potential-step techniques in stationary Solution 52 III. Potential-scan techniques in stationary Solution 78 IV. Controlled-potential techniques in flowing Solution 111 References 124 4 Large-Amplitude Controlled-Current Techniques 129 William R. Heineman and I. Controlled-current techniques in stationary Solution 129 II. Controlled-current techniques in flowing Solution 142 References 142 vii üi
Content Small-Amplitude and Related Controlled-Potential 143 Techniques I. Introduction 143 II. Frequency-domain techniques 148 III. Time-domain techniques 152 IV. Conclusion 160 References 160 Introduction to Analog Instrumentation 163 I. Classical controlled-potential instrumentation 163 II. Controlled-potential instrumentation based on operational amplifiers 171 III. Classical controlled-current instrumentation 186 IV. Controlled-current instrumentation based on operational amplifiers 187 V. Microprocessor-based electrochemical instrumentation 190 VI. Conclusion 192 Reference 192 Overcoming Solution Resistance with Stability and Grace in Potentiostatic Circuits 193 David K. Roe I. Introduction 193 II. Input-output relations of cells and potentiostats 197 III. Stability of potentiostat-cell circuits and the role of R u 204 IV. Compensation for ir u by positive feedback 216 V. Achieving stability through gain-frequency shaping 222 VI. Real Systems 231 Appendix 231 Bibliography 234 Conductivity and Conductometry 235 F. James Holler and Christie G. Enke I. Some basic relationships 237 II. DC contact measurement of conductance 243 III. Capacitive contact measurement of conductance 251 References 265 Mercury Electrodes 267 Zbigniew Galus I. Introduction 267 II. Dropping mercury electrode 268 III. Hanging mercury drop electrode 277 IV. Static mercury drop electrode 281 V. Streaming mercury electrodes 284
Contents IX VI. Mercury film and other types of mercury electrodes 284 References 286 10 Carbon Electrodes 289 Glenn Dryhurst and David L. McAllister I. Introduction 289 II. Spectroscopic graphite electrodes 290 III. Carbon paste electrodes 294 IV. Pyrolytic graphite electrodes 302 V. Glassy carbon electrodes 308 VI. Reticulated vitreous carbon electrodes 310 VII. Miscellaneous carbon electrodes 312 VIII. Sources of materials 317 References 317 11 Film Electrodes 321 Nicholas Winograd I. Introduction 321 II. Properties of film electrodes 322 III. Semiconducting film electrodes 325 IV. Metal film electrodes 329 V. Techniques of cell design based on film electrodes 332 References 334 12 Electrochemical Cells 337 Fred M. Hawkridge I. Design concepts 337 II. Stationary-solution experiments 343 III. Convected-solution experiments 347 IV. Thin-layer-cell design 355 V. Cells for spectroelectrochemistry 360 References 364 13 Solvents and Supporting Electrolytes 367 Albert J. Fry and Wayne E. Britton I. Introduction 367 II. Recommended solvents and electrolytes 371 III. Some other solvents 372 IV. Solvent and electrolyte-dependent phenomena 373 V. Experimental procedures 375 Appendix: Other literature 379 Acknowledgments 380 References 380 14 Vacuum Line Techniques 383 Csaba P. Keszthelyi I. Introduction 383 II. Vacuum line 384 III. Electrochemical glassware for the vacuum line 391 IV. Experimental methods 395 References 399
X Contents 15 Electrochemistry in the Dry Box 403 Steven N. Frank and Su-Moon Park I. Introduction 403 II. Choosing an inert-atmosphere System 405 III. Experimental 408 Appendix 414 References 415 16 Digital Simulation of Electrochemical Problems 417 J. T. Maloy I. The finite difference representation of Fick's laws 417 II. Defining the model diffusion coefficient 420 III. Defining At and Ax 421 IV. Establishing initial and boundary conditions 423 V. Dimensionless parameters 426 VI. A sample FORTRAN program 428 VII. Chronocoulometry 432 VIII. Other Nernstian electrode boundary conditions 436 IX. Homogeneous kinetics 439 X. Parametric substitutions 444 XI. Electrogenerated chemiluminescence 446 XII. Chronopotentiometry 447 XIII. Linear sweep voltammetry 450 XIV. Simulation of rotating disk hydrodynamics 451 XV. Simulation of rotating ring-disk behavior 453 XVI. Beyond the basic techniques 455 References 460 17 Electrochemical Evaluation of the Mechanisms of Organic Reactions Through Examples 463 M. Dale Hawley I. Introduction 463 II. Reduction of p-chlorobenzonitrile 464 III. Oxidation of adrenaline 470 IV. Oxidation of a-tocopherol 475 V. Concluding remarks 481 References 481 18 Selected Aspects of Transition Metal Electrochemistry 483 William E. Geiger I. Introduction 483 II. Significance of electrochemical potentials 484 III. Mechanisms and reactions of electrogenerated complexes 489 References 497
Contents xi 19 Electrochemical Preconcentration 499 William R. Heineman, Harry B. Mark, Jr., John A. Wise, and Daryl A. Roston I. Introduction 499 II. Electrochemical Stripping analysis 500 III. Spectroscopic analysis 521 References 535 20 Constant-Current Coulometry 539 David J. Curran I. Introduction 539 II. Coulometrie generation of reagents 540 III. Coulometrie titrations 551 References 566 21 Application of Electrochemistry to Pharm aceutical Analysis 569 Marvin A. Brooks I. Introduction 569 II. Coulometrie methods 575 III. Voltammetric methods 582 References 604 22 Electrochemical Detection in Liquid Chromatography and Flow Injection Analysis 611 I. Introduction 611 II. Transducer design 615 III. Applications review 630 IV. Conclusion 633 References 634 23 Photoelectrochemistry and Electrochemiluminescence 637 Hiroyasu Tachikawa and Larry R. Faulkner I. Introduction 637 II. Photoelectrochemistry at semiconduetor electrodes 638 III. Photoemission from metal electrodes 655 IV. Electrochemical monitoring of photolytic intermediates 658 V. Electrochemiluminescence 660 Appendix: Structures of cited molecules 669 Aeknowledgments 670 References 670 24 Principles and Techniques of Electrochemical-Electron Spin Resonance Experiments 675 Ira B. Goldberg and Ted M. McKinney I. Magnetic resonance in electrochemical studies 676 II. Molecular Orbitals in electrochemistry and ESR 677 III. Principles of ESR 679 IV. ESR Instrumentation 691 V. Experimental methods of ESR-electrochemical studies 699
XII Contents VI. Selected applications of ESR and electrochemical measurements 714 Appendix I: Selected bibliography 722 Appendix II: Units 724 References 725 Index 729