Differential Pulse Voltammetric Determination of Ascorbic Acid on Poly-p-Aminobenzene Sulfonic Acid Modified Electrode

Poly-p-aminobenzene sulfonic acid was modified on glassy carbon electrode by cyclic voltammetric electropolymerization, which was abbreviated as PABSA/GCE. In comparison with the bare GCE, a significant oxidation peak of ascorbic acid at the modified electrode in PBS of pH 5.0 was observed. It was found that the modified electrode exhibited excellent electrocatalytic responses towards the oxidation of ascorbic acid. Under the optimized conditions, linear relationship between values of oxidation peak current and mass concentration of ascorbic acid was kept in the range of 1.2-320 mg·L-1 with detection limit (3S/N) of 0.4 mg·L-1. Test for recovery was made by standard addition method using VC tablets as matrix, giving results in the range of 98.1% to 105%.