Objective: To establish a new method for determining the content of protopine in Corydalis Rhizome

and set up the limitation standard of protopine through determining the content of the samples from different origions. Method: HPLC method was used. The separation was performed on a Aglient TC-C18 column (4.6 mm×250 mm

5 μm) with mobile phase of acetonitrile-3% glacial acetic acid solution (contain 0.8% triethylamine) (18:82). The flow rate was 1.0 mL·min-1and the detection wavelength was set at 289 nm. Result: The calibration curves showed good linear regression within test ranges of 0.052-0.52 μg;the recovery was 99.44%. Conclusion: The method established for determining the content of protopine in Corydalis rhizome was accurate

simple and feasible. The content of protopine of the samples from different origions varied from 0.065% to 0.199% with the average content of 0.124%. It is suggested that the suitable content standard of Corydalis rhizoma should be no less than 0.09%.