Simultaneous Determination of the Contents of Liquiritin and Glycyrrhizic Acid in Licorice by Dual Wavelength-HPLC

Objective To establish a method for simultaneous determination of the contents of liquiritin and glycyrrhizic acid in licorice by dual wavelength-HPLC. Methods The gradient separation of liquiritin and glycyrrhizic acid in licorice was performed on a Lichrospher C18 column with a mobile phase consisted of acetonitrile-0.05 % phosphoric acid solution. The eluate was monitored by UV absorption at 220 and 255 nm, respectivity. Results This method could clearly separate liquiritin and glycyrrhizic acid peak from their nearby impurity peaks. The method was proved to be good linear correlations when injection amount were in a range from 0.02 μg to 2.40 μg for liquiritin and from 0.04 μg to 4.80 μg for glycyrrhizic acid. The relative standard deviations of the assays(n=5) were 1.09 % for liquiritin and 0.93 % for glycyrrhizic acid analysis. The stability of the component analysis was over 11 h after medicinal materials extracted. The average recoveries of liquiritin and glycyrrhizic acid were 93.1 % and 93.6 % for the licorice samples, respectively. Conclusion A simple and reliable high performance liquid chromatographic method was developed and validated for the simultaneous analysis of liquiritin and glycyrrhizic acid in licorice.