Detection and Characterization of Phorate and its Metabolites in Visceral Matrices by Mass Spectrometry

Authors: Sridhar L*, Samikkannu P and Satapathy KP

Volume 3, Issue 4

Abstract

Phorate is an Organophosphate insecticide that inhibits acetyl cholinesterase activity and is a systemic and contact insecticide and acaricide. Phorate is prone to undergo hydrolysis and oxidation in biological and environmental matrices. Consequently, screening, identification and characterization of the hydrolyzed, oxidized products of phorate in biological samples such as viscera and blood is an important task in the area of forensic toxicology. In a case study, Phorate and its major four metabolites Phorate sulfoxide, Phorate sulfone and Diethyl Dithiophosphoric were detected in the visceral matrices by Gas Chromatography Mass Spectrometry. Here we report successful detection and characterization of the Phorate and its major metabolites under positive ion Electron Ionization (EI) mass spectrometry. The EI mass spectra of the target compounds showed the molecular ion [M+•] in addition to the other diagnostic product ions that enable unambiguous identification of phorate and its metabolites. General fragmentation pattern of these compounds are discussed in detail. Phorate showed an ion at m/z 75 as the base peak corresponds to ethylthiomethylium (C2H4SCH2 +) ion. The Mclafferty rearrangement was also observed in Phorate and its metabolites. The identification of these compounds will be an invaluable support during investigation and in conviction of criminal cases in courts of law in phorate poisoning cases.

Keywords: Phorate; Phorate Sulfoxide; Phorate Sulfone; Diethyl Dithiophosphoric; GC-MS

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