Simultaneous Determination of Oleanolic Acid and Ursolic Acid in the Leaves of Forsythia suspensa by HPLC-ELSD

Objective: To establish an high performance liquid chromatography-evaporative light scattering detector(HPLCELSD) method for the simultaneous determination of oleanolic acid and ursolic acid in the leaves of Forsythia suspensa.Methods: The chromatographic separation was carried out on a Waters Symmetry C18column(4.6 mm× 250 mm,5μm) with a mobile phase composed of methanol and 0.4% acetic acid(93:7,V/V) at a flow rate of 0.4 mL/min.An evaporative light scattering detector was used to detect oleanolic acid and ursolic acid with a drift tube temperature of 80 ℃ and a gas pressure of 25 psi.Results: Both the developed calibration curves of oleanolic acid and ursolic acid revealed a good linear relationship over the ranges of 0.107-2.136 μg(r =0.9991) and 0.179-3.584μg(r= 0.9993),respectively.Therecovery ratesof oleanolicacid and ursolic acid were 98.67% and 98.56%,respectively.Conclusion: A simple,accurate and credible HPLC-ELSD method has been developed,which is suitable for the quality contro1 of the leaves of Forsythia suspensa.