Determination of organochlorine pesticide residues in foods using solid-phase extraction clean-up cartridges

Fourteen organochlorine pesticide residues in fatty foods were determined u sing a simple and rapid procedure based on solid-phase extraction (SPE) cle an-up cartridges with octadecyl (C-18)-bonded porous silica, a tandem C-18 and Florisil column, Alumina-N and Florisil. A Florisil cartridge eluted wi th 12 ml petroleum ether-ethyl ether (95 + 5) was the most efficient clean- up procedure capable of eliminating the matrix interference and satisfying the agreed acceptable recovery for the large numbers of organochlorine pest icides in nine kinds of foods having different fat contents. Average recove ries of organochlorine pesticides in shellfish, fish and meats ranged from 77 to 105%, 84 to 98% and 85 to 107%, respectively. In addition, analysis o f a certified Standard Reference Material (SRM 1945) verified the satisfact ory performance of Florisil clean-up cartridge. This SPE method not only yi elded comparable results for nonfatty foods, but also provided a reliable s eparation and quantification of organochlorine pesticides for analyzing a l arge number of foods with a wide range of fat content.