Resolution of ascorbic acid or catecholamine and indole alkaloid mixtures by pulse voltammetry at highly polished glassy carbon

Abstract

Metallographic polishing of glassy carbon electrodes (GCEs) yields well-defined oxidation peaks for two- and three-component mixtures of ascorbic acid, dopamine (DA), catechol, and hydroquinone. Linear calibration plots of differential pulse voltammetric current versus concentration were obtained for each component at a range of 0.4 to 10 μM, Deterioration of voltammograms was observed when highly, polished GCE was aged in solution, resulting in positive shifts and broadening of the peaks. Lower limits of detection (LLD) in water at pH 7 were about 0.01 μM, for DA and 1 μM for AA. Highly polished GCEs were further applied to mixtures of naturally occurring indole alkaloids.