Abstract: The electrochemical oxidation of L-cysteine in an SDS/BA/H₂O microemulsion system was studied with the methods of ultramicroelectrode cyclic voltammetry and AC impedance. The catalytic efficiency of the microemulsion on the electrochemical oxidation increases with the increase of BA or SDS content, but decreases with the increase of the water content because of the effects of BA, SDS and water on the solubilization of L-cysteine in the microemulsion. Furthermore, the catalytic efficiency of the bicontinuous structure is greater than that of an O/W microemulsion system. The results derived from both the rate constant k⁰ and Gibbs free energy ΔG^≠ accord with those from the catalytic efficiency.

Key words: Sodium dodecyl sulfate, Microemulsion, Electrochemical oxidation, L-Cysteine