Determination of Dopamine and Uric Acid under Coexistence of Ascorbic Acid at Glassy Carbon Electrodes Pre-Treated in Adenosine Monophosphate Solutions

Abstract

Glassy carbon electrodes modified with adenosine monophosphate (AMP) were described. It was fabricated by electrochemical grafting the products of the electrochemical oxidation of adenosine monophosphate at 1.8 V (vs. SCE) on glassy carbon electrode (denoted as AMP/GCE). The modified electrode was applied to the electrocatalytic oxidation of dopamine, uric acid and ascorbic acid and resolved the overlapping of the anodic peaks of dopamine, uric acid and ascorbic acid into three well-defined voltammetric peaks in cyclic voltammetry or different pulse voltammetry. In the presence of 1.0 mM ascorbic acid, a linear range of 0.086-21 μM with a detection limit of 0.028 μM for dopamine and in the range of 7.2-140 μM with a detection limit of 0.61 μM for uric acid were obtained. The modified electrode shows excellent selectivity and good sensitivity, antifouling properties, which was attributed to the formation of highly conjugated oxidation product bearing quinone structure during the modification process.