Abstract: Objective To improve the method by comparative experiment discussion on method of content determination of Baicalin in Yinhuang Tablets. Methods Samples were extracted by 50%-methanal, then analyzed on C18 chromatography column (250 mm× 4.6 mm× 5 μm)with mobile phase consisted methanol-purified water-phosphoric acid (50:50:0.2) at the flow rate of 1.0 mL·min-1. The column temperature was maintained at 30℃ and the detection wavelength was set at 274 nm. Results Good linearig of baicalin was achieved in the concentration range of 14.26 ~ 85.54 μg·min-1 (r=0.999 6) and the average recovey was 98.47% (RSD=1.12%). Conclusion The improved method is reliable and accurate, simple and sensitive with good separation efficiency. It is more suitable for the quality control of Yinhuang tablets.

Key words: Yinhuang tablet, baicalin, HPLC