Chemically modified electrodes based on macrocyclic compounds for determination of Vitamin C by electrocatalytic oxidation

The voltammetric behavior of Vitamin C (L-ascorbic acid) at carbon paste electrodes and electrodes modified with aza macrocycles have been studied. The use of zinc complexes, formed in situ at the electrode surface reduced the overpotential for the oxidation of ascorbic acid by about 200 mV and enhanced the peak currents. Linearity was observed over the range of 0.6-500 mug/cm(3) with a detection limit of 0.1 mug/cm(3) by differential pulse voltammetry. The modified electrode was used for the determination of Vitamin C in multivitamin-multimineral pharmaceutical preparations, fruit juices and wine samples. (C) 2001 Elsevier Science B.V All rights reserved.