Determination of organochlorine pesticides in milk by electron capture capillary gas chromatography

The goal of this study was to develop an analytical method to determine the organochlorine pesticides residues in milk. The samples were loaded onto the self-packed diatomaceous earth columns, then eluted with 25 mt solvent mixture of n-hexane-acetone-ethyl acetate (4+2+1, v/v/v). After collection and concentration, the extracts were cleaned up by the Cls solid-phase extraction cartridges. Gas chromatograph/electron capture detector was used for determination. The average recoveries of milk which were spiked with 10 ng/mL of alpha-BHC, lindane, heptachlor, dieldrin, p,p'-DDD, and p,p'-DDT were above 92%. Limits of detection between 0.5-1.8 ng/mL were achieved.