Determination of 50 Common Pesticide Residues in Golden Siraitia Grosvenoriis by QuEChERS and High Performance Liqiud Chromatography£­Tandem Mass Spectrometry

KeyWord:golden siraitia grosvenoriis  pesticide residues  QuEChERS  high performance liqiud chromatography£­tandem mass spectrometry£¨HPLC£­MS/MS£©

Abstract:

      An improved QuEChERS/high performance liqiud chromatography£­tandem mass spectrometry£¨HPLC£­MS/MS£© was established for the determination of 50 common pesticide residues in golden siraitia grosvenoriis£®After extracted with water£­1%£¨volume fraction£© acetic acid acetonitrile£¬the samples were purified with a combined adsorbent of 900 mg MgSO4£¬450 mg PSA£¬300 mg C18 and 50 mg GCB£®Analytes were separated on Agilent Poroshell 120 EC£­C18 column£¨150 mm ¡Á 3.0 mm£¬2.7 ¦Ìm£©£¬using 0.05% formic acid solution£¨containing 10 mmol/L ammonium formate£© and 95% methanol£¨containing 10 mmol/L ammonium formate and 0.05% formic acid£© as mobile phases£®Electrospray ionization source was applied in positive and negative ionization£¨ESI+ and ESI-£© mode under multiple reaction monitoring£¨MRM£© mode£®Meanwhile£¬the external standard method was employed to obtain the matrix-matched calibration curve for quantitation£®Results showed that there existed good linear relationships for 50 pesticides in the respective concentration ranges£¬with their correlation coefficients£¨r£© larger than 0.99£®The limits of quantitation£¨LOQs£© were 0.01£­0.02 mg/kg£®The average recoveries at four spiked levels of 2 LOQ£¬5 LOQ£¬20 LOQ and 40 LOQ ranged from 60.7% to 115%£¬with relative standard deviations£¨RSDs£© less than 15% for over 95% pesticides£¬which met with the requirements for trace analysis£®This method is convenient and reliable£¬and it could be applied to the determination of multi-pesticide residues in golden siraitia grosvenoriis.