Objective: A method for simultaneous determination of matrine and oxymatrine in Xianning Linimentum was established by ultra performance liquid chromatography with tandem mass spectrometry (UPLC-MS-MS). Method: The UPLC separation was performed on C18 column (2.1 mm×50 mm

1.8 μm) by using methanol and water containing 0.1% formic acid as mobile phase with the gradient elution at a rate of 0.30 mL·min-1. The analytes were detected by tandem mass spectrometry under the positive ion mode with the ESI source and carried out in the multiple reaction monitoring (MRM) mode. Result: Under the optimum conditions

the calibration curves were linear in the range of 0.000 5-0.6 mg·L-1 for matrine

0.000 4-0.5 mg·L-1 for oxymatrine. The detection limits were 0.2

0.2 μg·L-1 respectively. The average recoveries of the three effective components were between 95.8% and 98.6% with all relative standard deviations not more than 1.9%. Conculsion: The developed method is simple

rapid and accurate

and suitable for the quality control of the two components in Xianning Linimentum.