A New Extractive Spectrophotometric Method for the Determination of Oxydemeton methyl in Relation to its Environmental and Toxicological Analysis

Abstract

In view of the wide agricultural use of oxydemeton methyl insecticide and its associated toxic effects, it has been determined in soil, water and food stuffs to assess its environmental relevance. A new, simple and sensitive extractive spectrophotometric method has been developed for the purpose. It is based on microwave assisted alkaline hydrolysis of insecticide to form 2-ethylsulfinyl-ethyl mercaptan and transformation of the latter through reaction with carbon disulphide and nickel(II) acetate into  methyl isobutyl ketone extractable yellow nickel(II) trithiocarbonate complex showing maximum absorbance  at 378 nm. The colour is stable for 6 h and Beer’s law is obeyed in the concentration range 2.46–49.2 µg mL^–1. The oxydemeton methyl in commercial formulation, residues on water, food stuffs and on five Indian soils of different soil characteristics has been determined by the proposed method. The leaching behavior in terms of ground water umbiquity scores (GUS) for oxydemeton methyl has the value from 0.67 to 0.82 classifying it as a non leacher.