Adsorption efficiency of poly(malachite green) films towards oxidation of ascorbic acid

Thickness of poly(malachite green) films electropolymerized on a glassy carbon electrode surface, the concentration of ascorbic acid, pH value of the solution, and accumulation time were found to affect the adsorption-controlled anodic peak current of ascorbic acid on this polymer film coated electrode. Adsorption efficiency, defined as the ratio of the active sites in polymer films to the amount of adsorbed ascorbic acid molecules, was then proposed and estimated from the comparison of mathematically simulated cyclic voltammograms with experimental ones. The concentration of ascorbic acid is the greatest parameter affected the adsorption efficiency. Poly(malachite green) film electropolymerized on the glassy carbon electrode was found to be not totally active towards oxidation of ascorbic acid when the concentration of ascorbic acid is too high or when the poly(malachite green) film is too thick. The potential shift of ascorbic acid on the modified electrodes was also discussed.