Multiresidue method for determination of organochlorine insecticides and polychlorinated biphenyl congeners in fatty processed foods.

A previously published gel permeation chromatographic (GPC) procedure for determination of organophosphorus insecticides is used to determine 24 organochlorine (OC) pesticide and 9 polychlorinated biphenyl (PCB) residues in 8 fatty preserved foods of vegetable and animal origin. Samples are extracted with methylene chloride and cleaned up by automated GPC with a Biobeads SX3 column and a methylene chloride-cyclohexane (15 + 85) eluant. Compounds are quantitated by gas chromatography/ mass spectrometry (GC/MS) with selected ion monitoring using a DB-5 column. Average recoveries of OC pesticides from samples fortified at 0.010-0.080 mg/kg ranged from 73 to 98%. Average recoveries of 9 PCB congeners spiked at 2 levels (0.0025 and 0.020 mg/kg) were between 85 and 104%. Quantitation limits were between 0.002 and 0.025 mg/kg, depending on the compound. The purified extracts were analyzed further by GC with electron capture detection (ECD), and the results were compared with those obtained by MS. Determination of some OC pesticides and PCB congeners was not possible by ECD because of matrix interference.

Multiresidue method for determination of organophosphorus insecticide residues in fatty processed foods by gel permeation chromatography.

A multiresidue method for quantitative determination of 39 organophosphorus compounds (parent pesticides and their major metabolites) in 7 fatty processed foods is described. Samples are extracted with methylene chloride and cleaned up by automated gel permeation chromatography with a Biobeads SX3 column and a methylene chloride-cyclohexane (15 + 85) eluant. Organophosphorus compounds are quantitated by capillary gas-liquid chromatography with flame photometric detection using OV-1701 and DB-5 columns. Average recoveries from samples fortified at 0.025-1 mg/kg ranged from 50.6% for dichlorvos to 185% for malaoxon. Determination limits were between 0.005 and 0.040 micrograms/mL. Results were confirmed by gas chromatography/mass spectrometry with selected-ion monitoring.