Determination of active ingredients of Polygonum cuspidatum Sied. et Zucc. by capillary electrophoresis with electrochemical detection

High-performance capillary electrophoresis with electrochemical detection (CE-ED) was employed to analyze active ingredients of Polygonum cuspidatum Sied. et Zucc. in crude herbs and compound medicines. trans-Resveratrol, emodin, chrysophanol, and them are major important active ingredients. Operated in a wall-jet configuration, a 300 pm diameter carbon-disk electrode was used as the working electrode, which exhibits good response at + 950 mV (vs. SCE) for the four analytes. Under the optimum conditions, these analytes were base-line separated within 27 min in a borax buffer (pH 8.7). Notably, excellent linearity was obtained over two orders of magnitude with detection limit (S/N = 3) ranged from 4.2 x 10(-7) to 5 x 10(-8) g mL(-1) for all analytes. This method was successfully used in the analysis of Polygonum cuspidatum Sied. et Zucc. and Jindan tablets with relatively simple extraction procedures, and the assay results were satisfactory.