Determination of liquiritigenin and isoliquiritigenin in Glycyrrhiza uralensis and its medicinal preparations by capillary electrophoresis with electrochemical detection

A simple, reliable, reproducible and sensitive method, based on capillary electrophoresis with electrochemical detection (ED), for the determination of liquiritigenin and isoliquiritigenin in Glycyrrhiza uralensis and its medicinal preparations was described. Operated in a wall-jet configuration, a 300 μm diameter carbon-disk electrode was used as the working electrode, which exhibits good responses at +1000 mV (versus SCE) for the two analytes. Under the optimum conditions, the analytes were base-line separated within 8 min, and excellent linearity was obtained in the concentration range from 5.0×10−4 to 1.0×10−6 mol/1. The detection limit (S/N = 3) was 4.7×10−7 and 2.9×10−7 mol/1 for liquiritigenin and isoliquiritigenin, respectively. This work provides a useful method for the analysis of traditional Chinese medicines.