Single-step separation of organochlorine pesticide residues from fatty materials by combined use of solid-matrix partition and C-18 cartridges

A rapid single-step partition step between n-hexane and acetonitrile on a two-cartridge system composed of Extrelut-3 with a C-18 cartridge connected downstream has been developed for the separation of organochlorine (OC) pesticide residues from oils and fats. The extract is cleaned up by Florisil minicolumn chromatography before gas chromatography with electron-capture detection. Carry over of fatty material through the partition step is in the order of 4-40 mg for ca. 1.0 g of different oil or fats loaded on the two-cartridge system. Recoveries of 15 OC pesticides from ca. 1 g of soya oil spiked were between 70 and 103% (except HCB=ca. 60%) at spiking levels in the range 0.02-0.1 mg/kg.