Determination of Bioactive Components in Polygonum perfoliatum L. by Capillary Electrophoresis with Electrochemical Detection

The major bioactive components in a Chinese herb named Polygonum perfoliatum L. including ferulic acid, vanillic acid, quercetin, caffeic acid and protocatechuic acid were simultaneously determined by capillary electrophoresis with electrochemical detection (CE-ED) in this paper. The effects of working electrode potential, pH and concentration of running buffer, separation voltage, and injection time on CE-ED were investigated. Under the optimum conditions, the five analytes could be separated within 17 min at a separation voltage of 18 kV in 10 mmol· L⁻¹ phosphate buffer (pH 9.2). A 300 µm diameter carbon disk electrode generated good responses at +0.95 V (vs. SCE) to the five analytes. The response was linear over three orders of magnitude with detection limits (S/N=3) ranging from 7.1×10⁻⁸ to 9.3×10⁻⁸ g·mL⁻¹ for the analytes. This proposed method could be successfully applied to the analysis of the real samples with relatively simple extraction procedures and satisfactory results.