Fast solid phase extraction of polychlorobiphenyls and chlorinated pesticide residues from mussels using Sep-Pak cartridges

A rapid method for the determination of chlorinated pesticides and polychlorinated biphenyls in mussels (Mytilus sp.) is reported. The mussel sample is homogenized and extracted with acetonitrile. The organic solution is concentrated and successively diluted with distilled water solution (12 g L-1 NaCl). The organic compounds from water solution are adsorbed onto a NH2 Sep-Pak cartridge. The clean-up step, in which the polychlorobiphenyls and chlorinated pesticides are separated in different eluates, is achieved by passing 25 mL of a 40% methanol aqueous solution through the NH2 Sep-Pak and the C-18 Sep-Pak cartridges connected in series. The polychloroblphenyls are desorbed from the NH2 Sep-Pak cartridge whilst the chlorinated peslicides are recovered from the C-18 Sep-Pak cartridge. In the separation of polychlorobiphenyls from the chlorinated pesticides tested in this work, only aldrin, heptachlor and 4,4'-DDD are partially adsorbed with the polychlorobiphenyls onto the NH2 Sep-Pak cartridge. The average recovery is greater than or equal to 95.0% with a relative standard deviation less than or equal to 5.0%. The limits of detection for different pesticides and polychlorobiphenyl congeners are 0.01 and 0.008 mu g Kg(-1). The final determination is carried out by capillary gas chromatography with ECD.