Youyuan Peng

Determination of baicalein, baicalin, and chlorogenic acid in Yinhuang oral liquid by capillary electrophoresis with electrochemical detection

Abstract The use of capillary electrophoresis with electrochemical detection is described for the simultaneous detection of three bioactive constituents-baicalin, baicalein, and chlorogenic acid in traditional medicinal preparations. The three analytes could be well separated within 12 min in a 60 cm length capillary with a separation voltage of 20 kV in a 15 mmol/L borate buffer (pH 9.2). The working electrode was a 300 µm diameter carbon disc electrode at a potential of +0.90 V (vs. SCE). The system demonstrated good long-term stability and reproducibility with RSD below 5% for both migration time and the peak current (n = 7). The proposed method has been successfully applied to analyze the three active components in Yinhuang Oral Liquid with satisfactory results.

Determination of Phenolic Compounds in the Hull and Flour of Buckwheat (Fagopyrum esculentum Moench) by Capillary Electrophoresis with Electrochemical Detection

Abstract A simple, reliable and reproducible method, based on capillary electrophoresis with electrochemical detection (CE‐ED), for the determination of phenolic compounds of buckwheat (Fagopyrum esculentum Moench) hulls and flour was reported. The mainly phenolic components consist of (−)‐epicatechin, rutin, hyperoside, and quercetin. Operated in a wall‐jet configuration, a 300 µm diameter carbon disk electrode was used as the working electrode, which exhibits good response at +0.90 V (versus SCE) for all relevant analytes. The potential effects of working electrode, pH and concentration of buffer, separation voltage, and injection time on CE‐ED were investigated. Under the optimum conditions, the analytes can be separated in a 50 mmol/L borate buffer (pH = 8.7) within 16 min. The response was linear over three orders of magnitude with detection limit (S/N = 3) ranging from 2 × 10−7 g/mL to 5 × 10−7 g/mL for all analytes. This method has been used for the determination of phenolic compounds in buchwheat (Fagopyrum esculentum Moench) hulls and flour, and the assay result was satisfactory.