Ultramicroelectrodes in kinetic investigations supported by simulation. A review with some additional examples

The potentialities of coupling ultramicroelectrodes and digital simulation techniques in the evaluation of the charge transfer constant, k °, of the half-wave potentials, E12, in multistep electrochemical reactions, of kinetic rate constants in complexation reactions, and of the responses of a ultramicroelectrode-based channel detector, are presented. The advantages of carrying out experiments under intermediate mass-transfer conditions are assessed. In the lack of theoretical studies, the digital simulation can offer quite accurate solutions to these complicated questions, which can be faced introducing proper modifications into a unique algorithm as long as the geometry of the electrode and the boundary conditions of the diffusion equation describing the electrochemical processes remain unchanged. The characteristic equations of the finite difference methods used in the simulations of the mass-transfer at ultramicroelectrodes are also described.