DETERMINATION OF RESIDUES OF METHYL- AND DIMETHYLCARBAMATE INSECTICIDES BY GAS CHROMATOGRAPHY OF THEIR 2,4-DINITROANILINE DERIVATIVES

A procedure was developed for determining residues of methyl- or dimethylcarbamates in plant materials. The dichloromethane extract of the crop is subjected to a coagulation step, carbamates are hydrolyzed with alkali, and the liberated amines are reacted with 1-fluoro-2,4-dinitrobenzene to form dinitroaniline derivatives that are determined by electron capture gas chromatography. Derivative formation is essentially quantitative. Background interference varied with different crops, but was usually less than the equivalent of 0.05 p.p.m. of carbamate. Recoveries from fortified samples of several crops were 90 to 100%. © 1969, American Chemical Society. All rights reserved.