Abstract: In order to establish a method of determining the content of glycyrrhizic acid in licorice extractum after polysaccharide was extracted, the optimization of chromogenic conditions and investigation of methodology were carried out with vanillin-sulfuric acid as color development reagent and 535 nm as the maximum absorption wavelength. Optimal reactive conditions for 0.25mL sample solution were obtained as follows: color development reagents 2.5 mL 6 mg/mL vanillin and 2.0 mL 75% H2SO4, temperature 75 ℃, reaction time 25 min. This method had high precision (RSD=4.39%, n=6), stability (RSD=1.09%, n=60) and average recovery (X=95.93%, RSD=4.62%, n=5) and was reliable to determine the glycyrrhizic acid in licorice extractum after polysaccharide was extracted featuring convenience, accuracy, high stability and reproducibility.

Key words: licorice extractum, glycyrrhizic acid, vanillin-H2SO4, content determination

摘要： 为了建立甘草提取甘草多糖后浸膏中甘草酸含量的测定方法，以香草醛-硫酸为显色剂，535 nm为最大吸收波长，进行了比色条件优化及方法学考察。结果表明：在0.25 mL待测液中，加入0.25 mL浓度为 6 mg/mL的香草醛溶液和2.0 mL 75%硫酸，在温度为75℃条件下反应25 min，显色效果最好。该法精密度高（RSD=4.93%，n=6），1 h内稳定（RSD =1.09%，n=60），平均加样回收率为95.93% （RSD=4.62%，n=5），是一种简便、准确、稳定和重复性好的检测脱糖甘草浸膏中甘草酸含量的方法。

关键词: 甘草浸膏, 甘草酸, 香草醛-硫酸, 含量测定