CLOSED-FORM APPROXIMATE EXPRESSIONS FOR THE ELECTROCHEMICAL RESPONSE OF MICROELECTRODES IN THE ZERO-RANGE LIMIT

We show that the electrochemical response of one or more microelectrod es can be described, in the limit of small size, by closed-form soluti ons of diffusion-kinetic equations, which, under appropriate and well- defined conditions, should give a good approximation to the actual res ponse. The predictions of the analytical solutions for the diffusion-k inetic model are compared with microelectrode array experiments of Bar d et al. and show excellent agreement. The analytical results make cle ar the various scaling properties of the solution, as a function of el ectrode size and spacings, as well as indicating the range of validity of the diffusion-kinetic model itself.