Electrocatalytic oxidation of ascorbic acid by ferrocene in lipid film cast on a glassy carbon electrode

A ferrocene-dimyristoyl phosphatidylcholine (DMPC) film electrode was prepa red by casting the solution of ferrocene and DMPC in chloroform onto a glas sy carbon electrode surface. Ferrocene retained in the biological membrane gave a couple of irreversible peaks of cyclic voltammogram. The electrode e xhibited good electrocatalytic activity for the oxidation of ascorbic acid (H(2)A) in phosphate buffer (pH 6.64) with an anodic peak potential of +340 mV (vs. Ag/AgCl). The anodic current was directly proportional to the squa re root of the scan rate below 150 mV s(-1). The influence of the pH value was investigated and it was observed that pH 6.64 was the suitable value to the anodic peak potential and current. The thickness of the film and the i nterference of uric acid were also studied. The electrode can be used to de termine H(2)A in the presence of equimolar uric acid. The catalytic peak cu rrent increased linearly with the concentration of H(2)A in the range of 1 X 10(-4)-5 X 10(-3) mol L-1.