A rapid method for the determination of organochlorine, pyrethroid pesticides and polychlorobiphenyls in fatty foods using GC with electron capture detection

A new, single-step extraction and purification method was developed for the separation of 26 organochlorine pesticides (OCPs), three pyrethroid pesticides (PPs) and six polychlorinated biphenyls (PCBs) from fatty foods of either animal or vegetable origin. The method includes homogenisation of extracted fat and diatomaceous earth. Separation was achieved using a mini Pasteur pipette where a matrix solid-phase dispersion extraction was carried out with only 5 mL of climethyl sulphoxide as an eluting solvent. A Pasteur pipette was joined to a prepacked slurry filled Florisil column, water deactivated to 15% where a liquid-liquid extraction and adsorption chromatography successively took place. The elution of C)CPs, PPs and PCBs was performed with n-hexane/diethyl ether. Recoveries for PCBs were from 81 to 86% and for OCPs 68 to 94%, except for beta-HCH, which gave lower, more variable recoveries. Excellent recoveries were obtained for pyrethroid pesticides, mostly more than 80%. The method was applied to 509 fatty samples for monitoring of these compounds. GC, with two columns connected to two electron capture detectors (ECD), was used.