Objective     To establish an accurate method for determining the baicalin content of Zhichuan mixture.      Methods     HPLC was performed using a Diamonsil C

18

column (250 mm×4.6 mm

5 μm) and a mobile phase consisting of methanol and 0.5% phosphoric acid (60∶40) at a column temperature of 25 ℃

a mobile phase flow speed of 1.0 ml/min

and a UV detection wavelength of 280 nm.      Results     Baicalin showed a good linear relationship in the concentration range of 0.952 to 6.664 μg/ml

with a linear regression equation of y=48.13647x-9.74570 (r=0.999 98). The average recovery rate was 96.21%. The relative standard deviation (RSD) was 0.3737% (n=6).      Conclusion     Above HPLC method is easy to perform and has high specificity and high repeatability. This method can be used in the determination of baic

alin in Zhichuan mixture.