Analysis of chlorothalonil and degradation products in soil and water by GC/MS and LC/MS

We present a method using gas chromatography (GC) and liquid chromatography (LC) coupled to a mass selective detector to measure concentrations of the fungicide chlorothalonil and several of its metabolites in soil and water. The methods employed solid-phase extraction using a hydrophobic polymeric phase for the isolation of analytes. In lake water, average analyte recoveries ranged from 70% to 110%, with exception of pentachloronitrobenzene that gave low recoveries (23%). The method detection limits were determined to be in the range of I and 0.1 mu g 1(-1) for the LC and GC methods, respectively. In soil samples, recoveries ranged from 80% to 95% for 4-ydroxy-2,5,6-trichloroisophthalonitrile (metabolite 11) and 1,3-dicarbamoyl-2,4,5,6-tetrachlorobenzene (metabolite 111). Limits of detection (LOD) were 0.05 and 0.02 mu g g(-1), respectively. Chlorothalonil and other metabolites were analyzed by GC giving recoveries ranging from 54% to 130% with LOD of 0.001-0.005 mu g g(-1). (c) 2007 Elsevier Ltd. All rights reserved.