Determination of Active Ingredients of Spatholobus Suberectus Dunn and Its Medicinal Preparations by Capillary Electrophoresis with Electrochemical Detection

Abstract

A method based on capillary electrophoresis with electrochemical detection has been developed for the separation and determination of epicatechin, emodin, syringic acid, vanillic acid, rhein, and protocatechuic acid in Spatholobus suberectus dunn and its medicinal preparations for the first time. The effects of a working electrode potential, pH and concentration of running buffer, separation voltage, and injection time on CE‐ED were investigated. Under the optimum conditions, the analytes could be separated in a 60 mmol L⁻¹ borate buffer (pH 9.0) within 26 min. A 300 µm diameter carbon disk electrode has a good response at +0.95 V (vs. SCE) for all analytes. The response was linear over three orders of magnitude with detection limits (S/N=3) ranging from 5×10⁻⁸ g mL⁻¹ to 2×10⁻⁷ g mL⁻¹ for the analytes. The method has been successfully applied to the analysis of a real sample, with satisfactory results.

Keywords:

• Capillary electrophoresis
• Electrochemical detection
• Spatholobus suberectus dunn

Acknowledgment

This work is financially supported by the Natural Science Research Foundation from Shanghai Science and Technology Committee. (Grant No. 04ZR14041).