Simultaneous Determination of 5 Pesticide Residues in Vegetables by Ultra High Performance Liquid Chromatography-Tandem Mass Spectrometry(UPLC-MS/MS)

KeyWord:abamectin  emamectin benzoate  imidacloprid  indoxacarb  zineb  dispersive solid phase extraction  ultra high performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS)

Abstract:

      An analytical method was established for the simultaneous determination of residues of abamectin£¬emamectin benzoate£¬imidacloprid£¬indoxacard£¬zineb in vegetables by ultra high pressure liquid chromatography-tandem mass spectrometry(UPLC-MS/MS).The samples were extracted with acetonitrile after treated with 0.1% NaOH(containing 10 mmol/L L-cysteine and 10 mmol/L EDTA-Na2)£¬and cleaned up by 0.2 g C18+0.05 g GCB matrix dispersive solid phase extraction.Five kinds of pesticides were separated on a Thermo Hypersil BDS C18(100 mm ¡Á 4.6 mm£¬2.6 ¦Ìm) column using 10 mmol/L NH4OH-acetonitrile as mobile phase by gradient elution£¬and determined by MS/MS.The results showed that the calibration curves were linear in the ranges of 50-2 000 ¦Ìg/L for zineb£¬and 5-200 ¦Ìg/L for the rest of analytes.The correlation coefficients were in the range of 0.995 1-0.999 9.The spiked concentration ranges were 0.5-500 ¦Ìg/kg for five compounds in bean£¬chilli£¬pakchoi£¬cucumber£¬asparagus and tomato samples£¬and the spiked recoveries were in the range of 70.8%-103.6% with relative standard deviations(RSD) of 4.5%-13.9%.The limits of detection for zineb ranged from 8.2 ¦Ìg/kg to 30 ¦Ìg/kg,and the limits of quantitation were in the range of 27-100 ¦Ìg/kg.The limits of detection for the rest of compounds were in the range of 0.02-0.7 ¦Ìg/kg,and the limits of quantitation were 0.07-2.3 ¦Ìg/kg.The method was rapid£¬accurate£¬economical and practical£¬and could meet the needs of daily inspection.