Quantification of 2,4-D on solid-phase exposure sampling media by LC-MS-MS

Three types of solid-phase chemical exposure sampling media: cellulose, polyurethane foam, and XAD-2, were analyzed for 2,4-dichlorophenoxyacetic acid (2,4-D) and the amine salts of 2,4-D. Individual samples were extracted into acidified methanol, and the extracts were analyzed via liquid chromatography-tandem mass spectrometry using electrospray ionization and a C(8) reversed-phase LC column. (13)C 2,4-D and a labeled benzoic acid (13)C or d5) were employed as the surrogate and internal standard, respectively. Over a three-year study of pesticide exposure among agricultural workers involving a high volume of analyses, values of average % recovery for (13)C 2,4-D on personal exposure samples ranged from 87 to 98 with a % relative standard deviation ranging from 7 to 12. The performance of the method compares favorably with that of the current National Institute for Occupational Safety and Health-recommended approach for the analysis of 2,4-D on these types of exposure sampling matrices.