Double potential step chronoamperometry at spherical electrodes and microelectrodes

A general and explicit analytical easy solution for double potential step chronoamperometry applicable to microelectrodes is presented. This solution considers that both electroactive species are initially present.The solution indicates that the smaller the electrode radius, the more notorious the influence of the diffusion coefficient ratio, so the use of microelectrodes is of great utility for determining the diffusion coefficients of the electroactive couple. The analytical solutions given until now can only be considered as partial solutions for this problem, since they lead to absurd results for electrode radii <10−2 cm.This equation has also been applied to the study of amalgamation processes and it could also be applicable to the study of the ionic transfer at hanging and microspherical electrolyte drop electrodes (i.e., liquid–liquid interfaces). In these last cases, the use of this equation is limited by the validity of Koutecký’s approximation, which neglects the electrode finite volume.