Cyclic Alternating-Current Voltammetry with a Platinum Electrode

Abstract

THE a.c. polarographic method of Brewer and Gutmann¹, in which a.c. instead of d.c. current is measured against polarization potential, has hitherto not been extended to the determination of compounds reducible or oxidizable at potentials more positive than the potential of dissolution of mercury. This limitation is due to the difficulty of reproducing a.c. current-voltage curves obtained with solid electrodes. Changes in the nature of the surface of the electrode are responsible for poor reproducibility in conventional voltammetry²; even worse results can be expected in a.c. voltammetry because changes in the nature of the electrode modify the impedance much more than the resistance of the double layer during the electrolytic process.