THEORY OF STATIONARY CURRENT POTENTIAL CURVES AT INTERDIGITATED MICROARRAY ELECTRODES FOR QUASI-REVERSIBLE AND TOTALLY IRREVERSIBLE ELECTRODE-REACTIONS

Analytical equations for steady‐state current‐potential curves at interdigitated microarray electrodes (IDA) were derived by the conformal mapping of the complex variable theory when the electrode reaction was quasi‐reversible and totally irreversible. In this technique, curved current lines in the IDA could be transformed into a set of parallel lines, as in a thin‐layer cell at a faced twin electrode. The current‐potential curves were a function of ko(we + wg)/D and were almost independent of the geometrical parameter, wg/(we + wg), where ko is the reaction rate constant, we is the common width of each microband anode or cathode, wg is the width of the gap between the anode and the cathode, and D is the diffusion coefficient. The quasi‐reversible domain was 0.2 < ko(we + wg)/D < 10. A polaro‐graphic log plot for the current‐potential curve did not fall on a straight line except for the reversible wave. A modified log‐plot method is presented in which the current‐potential curve can be transformed into a straight line. The transfer coefficient and ko can be evaluated from this technique. Copyright © 1990 VCH Publishers, Inc.