On the impedance of galvanic cells: III. Applications to alternating current polarography

The theory described in part I of this series J. H. Sluyters , Rec. trav. chim. 79 , 1092 (1960). is applied to alternating current polarography by treating the complex cell impedance and cell admittance as functions of d.c. voltage. It is proposed to plot a.c. polarograms in the complex impedance or admittance plane. By this method it is possible to reduce the uncertainty in the height of the peak caused by the base current. An exactly linear relationship between the quantity measured and concentration can be obtained over a large range of concentrations by means of a simple construction. The measurements can be performed over a wide range of frequencies. Consequently, in some cases, a higher sensitivity can be obtained, because the most favourable frequency can be chosen. The method is not only suitable for analytical purposes, but also for the determination of the fundamental constants of electrode processes (rate constants, diffusion constants and double layer capacities).