Radiometric determination of 11 carbamate pesticides in the nanogram and subnanogram ranges by means of cholinesterase inhibition

Abstract

This method for determining carbamates is based on the inhibiting action of these substances on acetylcholinesterase activity. The use of radioactively labelled acetylcholine as a substrate, the ensuing extractive separation of the radioactive acetic acid (formed by hydrolysis) and its radiometric determination permit to detect very small amounts of carbamates. The limit of detection for aldicarb, baygon, benomyl, bux, carbaryl, CIPC, matacil, phenmedipham and promecarb lies in the picogram range; that for barban and methomyl, in the nanogram range. The lower, linear parts of the curves for the different carbamates fall within the range 0.001-10 ng. The sensitivity (expressed as delta% inhibition/delta lg ng carbamate) ranges from 1.0 to 9.7.