高效液相色谱法测定板蓝根不同总酸部位中水杨酸的含量

目的建立高效液相色谱法测定不同pH值的板蓝根总酸部位中水杨酸的含量。方法采用pH梯度萃取法制备不同pH值的板蓝根总酸样品;并用高效液相色谱法,ODS-C18色谱柱（250mm×4.6mm,5μm）,流动相为乙腈-0.2%磷酸水溶液系统,流速为1.0mL·min^-1,检测波长：236nm,线性梯度洗脱,测定不同总酸部位中水杨酸的含量。结果水杨酸浓度在2.13～42.5μg·mL^-1与峰面积线性关系良好,r=0.9993。不同pH值的总酸部位中水杨酸含量分别为：0.00014%、0.000169%、0.00014%、0.00090%、0.00035%、0.00046%,RSD分别为1.3%、1.1%、1.2%、1.3%、1.1%、1.4%,平均加样回收率（n=9）为100.05%,RSD为1.0%,以pH2～3总酸中水杨酸含量为最高。结论该分析方法简便、准确、重现性好,可用于板蓝根不同pH值的总酸部位中水杨酸含量的测定。

Determination of salicylic acid in total acid extraction of Radix Isatidis by HPLC

Objective To determine the content of salicylic acid in different pH total acid extractions of Radix Isatidis. Methods The different pH total acid extractions of Radix Isatidis were prepared by pH-gradient extraction and the contents of salicylic acid in different total acid extractions were determined by HPLC based on a Kromasil C18 column （250 mm×4.6 mm, 5 μm） with a gradient elution solvent system composed of Acetonitrile - 0.2% HsPO4 water solution. The flow rate was 1.0 mL · min^- 1, and the detection wavelength was 236 nm. Results The linearity for salicylic acid was 2. 13-42.5 μg · mL ^-1 （r= 0. 999 3）. The contents of salicylic acid in different pH total acid extractions of RadiaIsatidis were 0.000 14%, 0.000 169%, 0.000 14%, 0.000 90%, 0.000 35%, and 0.000 46%. RSD were 1. 3%, 1.1%, 1.2%, 1.3% , 1.1%, and 1.4% respectively. Theaverauerecoverv （n=9） was100.05%.and RSD was 1.0%. The content of salicylic acid in pH 2-3 total acid extraction was the highest. Conclusion The HPLC method is simple, accurate and reproducible, which can be used for determining the content of salicylic acid in different pH total acid extractions of Radix Isatidis.