Detection of O,O-Diethyl-O-(2,5-dichlorophenyl) Phosphorothioate and O,O-Diethyl-O-(3,6-dichloro-2-pyridyl) Phosphorothioate in Meat Fat

Two previously unreported organophosphorus residues have been detected in meat fat. The first, O,O-diethyl-O-(2,5-dichlorophenyl) phosphorothioate, apparently results from the debromination of bromophos-ethyl, while the other, O,O-diethyl-O-(3,6-dicliloro-2-pyridyl) phosphorothioate, presumably arises by the monodechlorination of chlorpyriphos. Mass spectral evidence is presented in support of the assigned structures and gas-liquid chromatographic retention data for the residues and their oxygen analogs are provided.