DEVELOPMENT OF A METHOD OF ANALYSIS FOR 46 PESTICIDES IN FRUITS AND VEGETABLES BY SUPERCRITICAL-FLUID EXTRACTION AND GAS-CHROMATOGRAPHY ION-TRAP MASS-SPECTROMETRY

A multiresidue method using supercritical fluid extraction (SFE) and g as chromatography/ion trap mass spectrometry (GC/ITMS) was developed f or analysis of 46 pesticides in fruits and vegetables, The SFE procedu re used 2 commercial instruments that trapped the extracts on solid-ph ase material, Silica gel chemically bound to octadecylsilane (ODS) col lected the extracted pesticides efficiently, and elution of the trap w ith acetonitrile gave high recoveries, Extracts thus obtained were suf ficiently clean for subsequent GC/ITMS analysis, The SFE conditions we re 320 atm and 60 degrees C (0.85 g/mL CO2 density) and 1.6 mL/min CO2 flow rate for 6 extraction vessel volumes. Trapping on 1 mL ODS occur red at 10 degrees C, and a 0.4 mL/min flow rate of acetonitrile at 40 degrees-50 degrees C was used to elute the pesticides, Quantitative an d qualitative analyses of the 46 pesticides were performed simultaneou sly by GC/ITMS, Studies of fortified samples gave >80% recoveries for 39 pesticides, and recoveries of >50% for the other pesticides, except methamidophos and omethoate, Grapes, carrots, potatoes, and broccoli were used as samples during method development, and a blind experiment involving incurred and fortified samples was used to test the approac h, Results of the blind study compared satisfactorily with results fro m 7 laboratories using traditional GC detectors and solvent-based extr actions.