Spectrofluorimetric determination of the insecticide azinphos-methyl in cultivated soils following generation of a fluorophore by hydrolysis

A rapid and simple spectrofluorimetric method for determining residues of the pesticide and acaricide azinphos-methyl in soil is described. Soil is extracted with methanol. The method is based on the alkaline hydrolysis of the insecticide to its main metabolite anthranilic acid. A detailed study of the parameters affecting the chemical hydrolysis is presented and the results are discussed. The calibration graphs were linear from 30 to 1000 ng ml–1, with a limit of detection of 8 ng ml–1. The precision of the method is 2% at the 60 ng ml–1 level. Recoveries of spiked soil samples were between 105 and 111%.