Sweep Co-Distillation Cleanup of Milk for Determination of Organophosphate and Chlorinated Hydrocarbon Pesticides

Abstract

Abstract A rapid extraction and sweep co-distillation cleanup procedure is described for organopliospbate and chlorinated pesticide residues in milk. Ethyl acetate and methanol are used as the extracting and the coagulating solvents, respectively. The extraction apparatus includes a graduated cylindrical separatory funnel which expedites sample handling. A suitable aliquot of the extract is concentrated in a Kuderna-Danish concentrator, sweep co-distilled for 30 min to remove the fat, and determined by GLC with the thermionic detector. Milk samples were fortified, on a whole milk basis, prior to extraction with three different pesticide standard solutions. The pesticide solutions contained as follows: (2) diazinon, methyl parathion, malathion, parathion, and Trithion; (2) Thimet, ronnel, ethion, Imidan, and Cuthion; and (3) lindane, heptachlor, aldrin, heptachlor epoxide, dieldrin, endrin, and p,p'-DDT. Average recoveries of these pesticides were generally 90+%. Sensitivity of 0.01 ppm was readily obtainable for pesticides such as parathion