Residues of Chlorpyrifos Insecticide in Various Crops. I. Sweep Co-Distillation Method for Extraction and Cleanup

Abstract

Abstract The sweep co-distillation technique was expanded for application to chlorpyrifos insecticide residues in various substrates. The published technique was followed without significant changes for samples of lettuce, carrot, sugar beet (leaves and roots), potato, apple, onion, cauliflower, orange (pulp and peel), corn grain, and agricultural soil. Recoveries ranged from 74.2 to 100.7% at the fortification level of 0.1 ppm. Recovery tests were carried out also at levels ranging from 0.05 to 1.0 ppm for some crop samples obtained from trial field tests, with good results. For tobacco samples, some changes in the extraction and cleanup procedure were introduced to avoid some GLC interferences, but recoveries were low. Low recoveries were also obtained from the unmodified method and from the extraction, partition, and Florisil cleanup method.