In Vitro Stability and Recovery of Insecticides from Milk1

Abstract
Recoveries of Sevin® (1-naphthyl N-methylcarbamate), Kepone® (decachlorooctahydro-1,3,4-metheno-21f-cyclobuta [ed] pentalen-2-one), Bayer 29493 (O,O-dimethyl O-[4-(methylthio)-m-tolyl] phosphorothioate), Bayer 22408 (O-naphthalimido-O,O-diethyl phosphorothioate), Ruelene® (O-4-tert-butyl-2-chlorophenyl O-methyl methylphosphoramidate), and CoRal® (O,O-diethyI O-(3-ch loro-4-methylumbelliferonc) phosphorothioate) from milk ranged from 87% to 97% using acetonitrile and chloroform as the primary extraction solvents and acetonitrile-N-hexane as a cleanup procedure. This extraction procedure was somewhat less effective for removing known amounts of DDT and dieldrin from milk. Acetonitrile-chloroform extraction of milk was usually more efficient for removing insecticides than was a 2: 1 mixture of diethyl ether and N-hexane. Ruelene, Bayer 22408, and Bayer 29493 were stable In Vitro in raw milk for periods up to 14 days of incubation, but after 3 days incubation, some Co-Ral equivalents remained in the milk residue following acetonitrile-chloroform extraction.