The analysis of the organophosphorus pesticide, fenitrothion, by an infrared method

Abstract

An infrared method is described for determining the fenitrothion [OO-dimethyl-O-(3-methyl-4-nitrophenyl)-phosphorothioate] content of technical material after chromatography over silica gel. The fenitrothion is eluted with methylene chloride, and after evaporating the eluate to dryness the residue is dissolved in carbon disulphide to give a concentration of fenitrothion in the range 0·8 to 1·1 per cent. w/v. Measurements taken at three absorption peaks in conjunction with related minima are used to calculate the fenitrothion content from previously prepared calibration graphs that relate absorbance to fenitrothion content. The standard deviation of this method, based on ten samples of technical material, is 0·53 per cent.