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A NEW SW-846 METHOD FOR THE ANALYSIS OF TOXAPHENE AND TOXAPHENE CONGENERS IN SOLID AND AQUEOUS SAMPLES USING GAS CHROMATOGRAPHY / NEGATIVE ION MASS SPECTROMETRY
Citation:
SIVERTSEN, S. A NEW SW-846 METHOD FOR THE ANALYSIS OF TOXAPHENE AND TOXAPHENE CONGENERS IN SOLID AND AQUEOUS SAMPLES USING GAS CHROMATOGRAPHY / NEGATIVE ION MASS SPECTROMETRY. In Proceedings, National Environmental Monitoring Conference, WASHINGTON, DC, August 11 - 15, 2008.
Impact/Purpose:
The determination of toxaphene has typically been performed using GC-ECD. While GC-ECD is quite sensitive to electron-capturing species, it is also non-specific in its response, resulting in potential matrix interference. To tackle the complexity of GC-ECD toxaphene analysis, the US EPA is investigating an alternate determinative technique.
Description:
US EPA SW-846 methods have typically relied on dual column gas chromatography coupled with electron capture detection (GC-ECD) for analysis of low concentrations of organochlorine pesticides, including toxaphene, in environmental samples. Toxaphene is one of the most widely applied pesticides in the world and is a complex mixture of predominately polychlorinated camphenes estimated at 800-plus congeners. Once in the environment, toxaphene degradation begins. Weathered residues in environmental samples may not match laboratory standards. Adding to this complexity, degradation can result in metabolites not present in laboratory standards. To tackle the complexity of GC ECD toxaphene analysis, the US EPA is investigating an alternate determinative technique. The Agency is presently validating a method utilizing gas chromatography coupled with detection by low resolution methane negative ion mass spectrometry (GC NIMS) which uses scan or selected ion monitoring (SIM). Initial target analytes in the method are environmentally relevant toxaphene congeners as well as technical toxaphene. Using SIM, we were able to obtain congener limits of detection ranging from 0.00020-0.0026 µg/L for water and 0.0070-0.047 µg/kg for soils. This method is performance-based and allows for inclusion of other toxaphene congeners in extracts from solid and liquid matrices plus organochlorine pesticides routinely analyzed by Method 8081A.
