Colorimetric determination of dimethoate or omethoate

Abstract

A simple, sensitive and rapid colorimetric method is described for determining dimethoate [ O,O-dimethyl- S-( N-methylcarbanoylmethyl)phosphorodithioate] and omethoate by an enzymatic method using pig liver acetone powder as enzyme source and p-nitrobenzenediazonium fluoroborate as the chromogenic reagent. This colorimetric method is more sensitive than non-enzymatic methods. Inhibition can be detected at ng levels and amounts ranging from 50 to 1000 ng of omethoate and from 1 to 10 μg of dimethoate can be estimated.