Determination of rutin and quercetin in plants by capillary electrophoresis with electrochemical detection

A method based on capillary electrophoresis with electrochemical detection (CE-ED) was developed for the determination of daidzein, rutin and quercetin. The effects of some important factors such as the acidity and concentration of running buffer, separation voltage, injection time, and detection potential were investigated to acquire the optimum conditions. The working electrode was a 300 mu m diameter carbon disc electrode positioned opposite the outlet of capillary. The three analytes could be well separated within 10 min in a 40 cm length capillary at a separation voltage of 12 kV in a 100 mmol/l berate buffer (BB, pH 9.0). The response was linear over three orders of magnitude with detection limits (S/N = 3) ranged from 0.190 x 10(-6) to 0.434 x 10(-6) mol/l for all compounds. This proposed method demonstrated good long-term stability and reproducibility with relative standard deviations R.S.D.) of less than 5% for both migration time and peak current (n = 7). It has been successfully applied for the determination of rutin and quercetin in Chinese traditional drug, Flos Sophorae buds and in the leaves of Ligustrum lucidum Ait. and Cinnamomum camphora (L.) Presl. (C) 2000 Elsevier Science B.V. All rights reserved.