Determination of Nineteen Organophosphorus Pesticides in Vegetables by Gas Chromatography-Tandem Mass Spectrometry Combined with Dispersive Solid-phase Extraction and Dispersive Liquid-Liquid Micro-extraction

KeyWord:dispersive liquid-liquid micro-extraction  dispersive solid-phase extraction  gas chromatography-tandem mass spectrometry(GC-MS/MS)  organophosphorus pesticides  vegetables

Abstract:

      A gas chromatograpy-tandem mass spectrometric(GC-MS/MS) method for the determination of nineteen organophosphorus pesticides in vegetables was developed using dispersive solid-phase extraction(DSPE) and dispersive liquid-liquid micro-extraction(DLLME) as sample preparation methods.With dispersive solid-phase extraction,PSA and C18 were used as the sorbents,and acetonitrile as the eluted solvent.Some experimental parameters influencing the extraction efficiency,such as the types and volume of the dispersive solvents and extraction solvents were examined and optimized.Gamma-L-gulonic acid lactone(AP) used as a masking regent for compensation effect of matrix was evaluated.Under the optimum conditions,the recoveries of nineteen organophosphorus pesticides in pepper chili and shallot samples at fortified levels of 0.05,0.1,0.5 mg/kg ranged from 76.9%to 126.8%with relative standard deviations of 0.6%-7.3%.The limits of detection(S/N=3) were in the range of 0.10-0.50 ¦Ìg/kg.With the advantages of quickness,low toxicity and high enrichment factors,the proposed method is applicable for the analysis of organophosphorus pesticides in vegetables.