A solid phase exaction coupled with ultra high performance liquid chromatography-tandem mass spectrometric(UPLC-MS/MS) method was developed for the simultaneous determination of 19 pesticides in strawberry.After extraction with acetonitrile,purification with NH2 SPE cartridges and dissolution with methanol,the analytes were analyzed by UPLC-MS/MS on an Agilent Proshell120 EC-C18 column with a mixture of 0.1% formic acid-acetonitrile as mobile phase by gradient elution.The mass spectrometer was operated in multiple reactions monitoring(MRM) mode in positive mode.The purifying effects of 6 pretreatment methods were optimized by UPLC-Q-TOF.Matrix effects of real strawberries were studied.The limits of quantitation(LOQs),which were determined by adding standard solution to pesticide free strawberry samples,were 0.001 mg/kg for mandipropamid,bifenazate,picoxystrobin and pyraclostrobin and 0.01 mg/kg for the others.Good linearities were obtained for 19 pesticides in the concentration range of 0.000 5-1.0 mg/L with correlation coefficients more than 0.999.The fortified recoveries at low,intermediate and high concentration levels were in the range of 77.3%-100.3%,with relative standard deviations(RSDs) not more than 12.3%.False positive results were avoided effectively due to the methods good ablity of resistence matrix interference.All the above observations indicated that the established method was simple,efficient and sensitive,and was suitable for the determination of 19 pesticides in strawberry.
关键词
超高效液相色谱-串联质谱(UPLC-MS/MS)固相萃取(SPE)农药残留草莓
Keywords
ultra high performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS)solid-phase extraction(SPE)pesticidesresiduestrawberry设施草莓(Fragaria ananassa Duchesne)