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 polychlo rinated biphenyls in mussels (Mytilus sp.) is reported. The mussel sample i s homogenized and extracted with acetonitrile. The organic solution is conc entrated and successively diluted with distilled water solution (12 g L-1 N aCl). The organic compounds from water solution are adsorbed onto a NH2 Sep -Pak cartridge. The clean-up step, in which the polychlorobiphenyls and chlorinated pestici des are separated in different eluates, is achieved by passing 25 mL of a 4 0% methanol aqueous solution through the NH2 Sep-Pak and the C-18 Sep-Pak c artridges 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 te sted in this work, only aldrin, heptachlor and 4,4'-DDD are partially adsor bed with the polychlorobiphenyls onto the NH2 Sep-Pak cartridge. The average recovery is greater than or equal to 95.0% with a relative stan dard deviation less than or equal to 5.0%. The limits of detection for diff erent pesticides and polychlorobiphenyl congeners are 0.01 and 0.008 mu g K g(-1). The final determination is carried out by capillary gas chromatograp hy with ECD.