OPTIMIZATION OF AC VOLTAMMETRIC MEASUREMENTS AT ULTRAMICROELECTRODES

The precision of activation resistance measurements under ac voltammetric conditions was theoretically examined. In particular effects of the electron transfer rate constant, solution conductivity, double layer capacitance, stray capacitance of the circuit, electrode size, reactant concentration, frequency and electrode potential were analyzed. The results allow selection of optimal conditions for the determination of charge transfer kinetics from ac impedance experiments carried out with ultramicroelectrodes. It has been shown that in some systems the determination of rate constants up to 100 cm/s may be possible.