SIMULTANEOUS DETERMINATION OF DIFFUSION-COEFFICIENT AND CONCENTRATION BY CHRONOAMPEROMETRY AT A MICRODISK ELECTRODE

Abstract

Two unknown values among three electrochemical values, i.e. electrode area, diffusion coefficient, and concentration, are simultaneously obtained by nonlinear regression analysis of a single chronoamperometric faradaic current curve at a microdisk electrode. The approach is an analytical application of the semi-empirical equation presented by Shoup and Szabo for the chronoamperometric response at a disk electrode. To demonstrate the usefulness and accuracy of this approach, the chronoamperometric current at a platinum disk electrode of 50 mum radius in solutions of Ru(NH3)63+, ferrocene, Fe(CN)63-, and C60, were analyzed.