Simultaneous determination of sulfonylurea herbicides in ginseng by ultra performance liquid chromatography-tandem mass spectrometry

Abstract

An ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/ MS) method was developed for the determination of the fifteen sulfonylurea herbicides in ginseng. The pesticides were extracted with acetonitrile, cleaned-up by an ENVI-Carbon solid phase extraction cartridge, eluted with 1% formic acid in methanol-dichlormethane (20:80, v/v), separated with UPLC and detected with MS/MS in multiple reaction monitoring (MRM) mode via positive electrospray ionization (ESI+). The method was validated at three fortification levels in ginseng. The validation results were as follows. The standard calibration curves for the fifteen sulfonylurea herbicides all showed linear over the range of 2-100 microg/L with the correlation coefficients between 0.996 and 0.999. The average recoveries of the fifteen sulfonylurea herbicides at the three fortification levels of 5, 25 and 50 microg/kg were between 84.9% and 104.3% with the relative standard deviations (RSDs) between 2.4% and 11.9%. The limit of quantification (LOQ) was defined as the lowest concentration that could be measured with acceptable precision and accuracy. The LOQs of all the fifteen sulfonylurea herbicides in ginseng were 5 microg/kg. It was indicated that this method is easier, more sensitive and has a better purification effect. The sensitivity, accuracy and precision of the method were all acceptable. So, this method can be further applied to investigating the contamination status of traditional Chinese medicine by the sulfonylurea herbicides