Rapid Screening for Organochlorine and Organophosphorus Pesticide Residues in Fruits and Vegetables Using a Sold Phase Extraction Cleanup
F.J. Schenck and Michael K. Hennessy, Southeastern Regional Laboratory, FDA, Atlanta, GA 30319
A rapid multiresidue solid-phase extraction (SPE) method for the isolation and subsequent gas chromatographic determination of pesticide residues in fruits and vegetables has been developed. The method is a modification of published methods developed by regulatory agencies in Canada and New York State. Pesticides are extracted from fruit and vegetable samples with acetonitrile and water is separated from the extract by salting out. Matrix coextractants are removed from the extract using tandem graphitized carbon black (GCB) and aminopropyl SPE columns. Acetone/toluene (3:1) was used as an elution solvent. By optimizing the SPE elution solvent and size of the GCB SPE column, we were able to significantly reduce the volume of solvent required for the SPE cleanup step compared to previously published SPE methods. Recovery studies were performed using samples containing both fortified and incurred pesticide residues.