[Reverse-phase HPLC determination of coumarins in the traditional Chinese drug bai-zhi (Angelica dahurica forma bai-zhi)].

A reversed phase HPLC procedure has been developed for the separation and determination of oxypeucedanin (I), imperatorin (II) and isoimperatorin (III) in Bai-zhi simultaneously. I, II and III were extracted from Bai-zhi by using ether. The solution was evaporated to dryness and the residue was redissolved in 25 ml of ethyl acetate and 10 microliters of the solution were analysed on Waters mu Bondapak C13 column (300 x 3.9 mm ID) using methanol-water (70:30) as the mobile phase and detecting at 254 nm. The results were calculated by external standard method on the basis of peak area. The average recoveries of the standards added to the sample were 101.36, 100.54 and 97.91% for I, II and III respectively, and coefficients of variation were less than or equal to 3.33%. Analytical results by HPLC method are in agreement with those by TLC method. This method is rapid, reproducible and accurate and has been applied to analyse the contents of three components in 42 samples of angelica. The results of fourteen samples were given.