A study of potentiostat noise

This paper deals with a generalized version of the galvanostatic reversed coulostatic pulse method proposed by van Leeuwen and Sluyters. The potential of the working electrode is stepped to an appropriate potential by any kind of d.c. perturbation and then allowed to relax. The relaxing potential is perturbed again at an arbitrary time by a coulostatic pulse with polarity opposite to that of the first perturbation. The charge of the coulostatic pulse is adjusted so that the potential vs. time curve may have a horizontal tangent at an appropriate time after the end of the pulse. The overpotential at that time is known from the potential vs. time curves obtained with and without the coulostatic pulse. Analysis of experimental results is made on the basis of the rigorous solution for the boundary value problem of diffusion. The proposed procedure is tested with success by experiments on the trisoxalatoferrate(III)/(II) electrode and the corresponding equivalent circuit of Randles type. Its applicability to such an electrode reaction as involves an unstable product is suggested.