Content Determination of Baicalin and Emodin in Daochi Pills by HPLC

OBJECTIVE:To establish the method for the content determination of baicalin and emodin in Daochi pills.METHODS:HPLC was adopted with chromatrex C18 as column.The mobile phase for baicalin determination consisted of methanol-water-phosphoric acid(43:57) with detection wavelength at 280 nm.The flow rate was set at 1.0 mL·min-1 and the column temperature was 30 ℃.The mobile phase for emodin determination was methanol-water-glacial acetic acid(80:20) with detection wavelength at 245 nm.The flow rate was 1.0 mL·min-1 and the column temperature was 25 ℃.RESULTS:There was good linearity between the peak area and concentration within the ranges of 0.626～1.044 mg·mL-1(r=0.999 6) for baicalin and 5～25 μg·mL-1(r=0.999 8) for emodin,respectively.The average recoveries of baicalin and emodin were 100.18%(RSD=0.75%)and 99.30%(RSD=1.5%),respectively(n=9).CONCLUSION:The method is simple,accurate and specific for quality control of Daochi pills.