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 querceti n. The effects of some important factors such as the acidity and concentrat ion of running buffer, separation voltage, injection time, and detection po tential were investigated to acquire the optimum conditions. The working el ectrode was a 300 mu m diameter carbon disc electrode positioned opposite t he outlet of capillary. The three analytes could be well separated within 1 0 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 orde rs 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 demonstrate d good long-term stability and reproducibility with relative standard devia tions 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 qu ercetin in Chinese traditional drug, Flos Sophorae buds and in the leaves o f Ligustrum lucidum Ait. and Cinnamomum camphora (L.) Presl. (C) 2000 Elsev ier Science B.V. All rights reserved.