STEAM DISTILLATION-SOLVENT EXTRACTION, A SELECTIVE SAMPLE ENRICHMENT TECHNIQUE FOR THE GAS-CHROMATOGRAPHIC ELECTRON-CAPTURE DETECTION OF ORGANOCHLORINE COMPOUNDS IN MILK POWDER AND OTHER MILK-PRODUCTS

The application of a simultaneous water steam distillation-organic solvent extraction (SDE) method for the GC-electron-capture detection of hexachrorobenzene, alpha-hexachlorocyclohexane (alpha-HCH), gamma-HCH, cis-heptachlorepoxide, 2,4'-DDE, 4,4'-DDE, dieldrin, 2,4'-DDT and 4,4'DDT in milk powder and other milk products is described. The SDE apparatus was a newly designed modification of the apparatus of Likens and Nickerson and Godefroot and co-workers and light petroleum was used as the extraction solvent. The method extracted the organochlorine pesticides selectively and with high recovery from interfering matrix compounds. Extraction and clean-up were performed in one step,followed by a simple concentration step. Quantification was performed using pentachlorobenzene and Mirex as internal standards. The limit of determination was between 0.5 and 2 ng/g, depending on the analyte.