Determination of four active ingredients in Vc Yinqiao tablets by capillary zone electrophoresis with amperometric detection

A simple, reliable and reproducible method, based on capillary zone electrophoresis with amperometric detection (CZE-AD), has been developed for simultaneous determination of four active ingredients in Vc Yinqiao tablets including paracetamol, vitamin C, caffeic acid and chlorogenic acid. A carbon-disk electrode was used as working electrode and 0.95 V (versus SCE) was selected as detection potential. The optimal conditions of CZE experiment were 30 mmol center dot L-1 borate solution (pH 9.5) as running buffer, 14 kV as separation voltage and 8 s (14 kV) as electro-kinetic sampling time. Under the selected optimum conditions, paracetamol, vitamin C, caffeic acid and chlorogenic acid could be perfectly separated within 22 min, and their detection limits (S/N = 3) ranged from 5 X 10(-7) to 1 X 10(-6) mol center dot L-1. This proposed method demonstrated good reproducibility with relative standard deviations of less than 3% for both migration time and peak current (n = 7). The utility of this method was demonstrated by monitoring a kind of compound medicine named Vc Yinqiao tablets and the assay results were satisfactory.