Differential electrolytic potentiometry with periodic polarisation. Part XXIV. An appraisal of the amplitude-biassed mode

Abstract

A simple device for amplitude biassing a periodic waveform without distortion has been developed to overcome the difficulty with earlier instrumentation of obtaining more than a 2% bias. Amplitude-biassed differential electrolytic potentiometry has been compared with zero-current potentiometry, classical d.c., symmetrical periodic and time-biassed periodic differential electrolytic potentiometry in oxidation-reduction titrimetry for electrode reactions of various rates, and in acid-base titrimetry. The behaviour of individual electrodes with reference to zero-current and standard electrodes has been examined. The behaviour observed is in accord with theoretical prediction, and is analogous to the application of a d.c. offset to symmetrical periodic polarisation. The advantages of rapid potential equilibration and extended electrode life between activations accrue, but with appreciable bias the endpoint periodic signal deviates from the equivalence point.