The electrochemical copolymerization of 3,4-dihydroxybenzoic acid and aniline at microdisk gold electrode and its amperometric determination for ascorbic acid.

The electrochemical copolymerization of 3,4-dihydroxybenzoic acid (3,4-DHBA) and aniline was carried out at microdisk gold electrodes by means of cyclic voltammetric sweep. The polymer obtained on the electrode shows good electrochemical activity and high stability even though in neutral and weakly basic media. It was found that the response current of ascorbic acid was greatly enhanced at this composite polymer electrode. Moreover, the anodic overpotential was significantly reduced for about 200 mV (vs. SCE) compared with that obtained at bare gold electrodes. The electrode exhibits a rapid current response (less than 2 s) and a high sensitivity (0.21 AM(-1) cm(-2)). The dependence of response currents on the concentration of ascorbic acid was linear in the range of 1.0x10(-4)-1.0x10(-2) M. In addition this composite polymer modified electrode exhibits a high electrode stability for a long-term use.