Acid Ammonium Acetate Extraction and Electron Capture Gas Chromatographic Determination of Carbofuran in Soils

Abstract

Abstract A method is presented for determining carbofuran residues in soils that gives improved recovery, especially in weathered soils, and allows quantitation of as little as 0.1 ppm without cleanup. The soil is extracted with 0.5M acid ammonium acetate and the carbamate in the extract is determined by electron capture gas chromatography as the dinitrophenyl ether. A systematic study was conducted to optimize extraction conditions. In tests of soils fortified with 1 ppm carbofuran, using optimized extraction conditions, recoveries varied with soil type, ranging from 61% in a peat to 92% in a silt loam. Recoveries of the metabolites 3-hydroxy- and 3-ketocarbofuran from field soils were at least as efficient as by HCl extraction. In addition to carbofuran, other methylcarbamate insecticide residues that may be determined by this method include Landrin, propoxur, and Bux.