Study on the Influence of Different Methods of Preparation to the Contents of Rutin and Quercetin in Flowers and Flower Buds of Sophora Japonica L by Capillary Zone Electrophoresis

A method of capillary zone electrophoresis (CZE) was proposed for the determination of rutin and quercetin in flowers and flower buds of Sophora Japonica L and it was applied to the study of influences of different methods of preparation of this Chinese medicine to the contents of rutin and quercetin in it. Main conditions of the method,including pH value of buffer and its concentration and applied voltage for separation,organic additives,and their concentrations and the time of sample introduction,were studied and optimized. Under the optimum conditions,the separation of rutin and quercetin was completed within 5 min and the quantitative analysis was performed by UV-detection at 214 nm. Linearity were kept in the range of 0.04-1.8 g·L-1 of rutin (r=0.999 2) and 0.02-2.0 g·L-1 of quercetin (r=0.999 4) with detection limits (S/N=3) of 8 and 5 mg·L-1 respectively. The results obtained by this method proved that the contents of rutin and quercetin in flowers and flower buds of Sophora Japonica L were remarkably affected by different methods of preparation.