Polyurethane Foam as Trapping Agent for Airborne Pesticides: Analytical Method Development

摘要

A method for determining levels of organochlorine, organophosphorus, and N-methyl carbamate insecticides in air was developed using 4.4 cm-diameter plugs of polyurethane foam as traps and a modified Sherma-Shafik multiresidue procedure for analysis of foam extracts. With this method, the minimum detectable air concentrations for vapors of 17 of the 18 organochlorine and organophosphorus pesticides tested was 0.1 nanogram per cubic meter or less. Six carbamate pesticides did not volatilize in sufficient amounts to allow analysis. The experimental program consisted of measurements of efficiency of foams for trapping vapors and aerosols, tests of foam compression during air sampling, evaluations of extraction solvents, evaluations of techniques for extracting pesticide residues from the foams, comparisons of the performance of the ester and ether forms of polyurethane foam, evaluations of the steps in the Sherma-Shafik analytical procedure, evaluations of GLC columns and instrumental parameters, and tests of derivatization procedures for electron-capture gas chromatography of the N-methylcarbamates. A 10-cm depth of foam was found to be an efficient trap for vaporized pesticides. Five-cycle Soxhlet extraction with 1:1 hexane-acetone was the best procedure for removal of pesticides from foam plugs.