Separation and Detection of Electrochemical Active Compounds in Houttuynia cordata Thunb. by Reversed-Phase High-Performance Liquid Chromatography with Electrochemical Detection

A reliable and sensitive method of reversed-phase high-performance liquid chromatography-electrochemical detection (HPLC-ECD) was established for the simultaneous determination of five electrochemical active compounds (chlorogenic acid, rutin, hyperoside, quercitrin, and quercetin) in Houttuynia cordata Thunb. Chromatographic separation was carried out on a reversed-phase C18 column and a mobile phase comprised of 0.04 mol/L phosphate buffer (pH 4.5) and acetonitrile with gradient elution by amperometric detection with a glassy-carbon electrode at the working potential of +0.80 V. The method was validated for linearity, accuracy, precision, and limit of quantitation and detection. Under the optimized conditions, linear regression analysis for the calibration curve showed a good linear relationship with a regression coefficient beyond 0.999 between peak area and their concentrations in the linear range of 50.0 ng/mL–10.0 µg/mL for chlorogenic acid and rutin, 30.0 ng/mL–10.0 µg/mL for hyperoside, quercitrin, and quercetin, respectively. The limits of detection were found to be 5.0–20.0 ng/mL. The proposed method could be applied to the analysis of five compounds present in Houttuynia cordata Thunb. with satisfactory results.