United States Environmental Protection Agency, National Homeland Security Research Center; Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health
Washington, DC: U.S. Environmental Protection Agency, EPA/600/R-12/581, 2012 Aug; :1-30
The U.S. Environmental Protection Agency (EPA) is charged with developing tools and methodologies that enable the rapid characterization of indoor and outdoor areas and water systems following terrorist attacks or natural or manmade disasters. Chemical warfare agents (CWAs) and their degradation products remain a high-priority concern due to the presence of primary warfare agents in the U.S. chemical warfare agent inventory and some CWA degradation products can be as toxic as the parent compounds. Nitrogen mustard agents are vesicant CWAs which can break down into environmentally persistent degradation products. Sample stability studies suggest nitrogen mustard degradation products can persist in the environment for several weeks, and probably much longer depending on the associated environmental conditions. If an incident were to occur within an indoor setting, versatile sampling procedures are needed to detect CWA degradation products from various CWAs, including nitrogen mustard, from multiple types of contaminated surfaces (e.g., walls, floors and furniture). Several different wipes were tested, but only the filter paper wipe was considered viable straight out of the box. Filter paper wipes were selected over other wipes (including cotton gauze and non-woven polyester fibers) because they did not contain peaks that interfered with the target analytes, resulted in the highest percent recoveries and the lowest background levels during sample analysis. For nitrogen mustard and its degradates, cotton gauze would be an inappropriate choice unless the gauze is pre-cleaned and treated prior to use, a time-consuming and potentially costly approach, due to the contamination of TEA and DEA within the wipe. Sampling kits provided to samplers in the field, equipped with pre-packaged cotton gauze, would need to be tested to ensure that targeted analytes are not present, whereas no pretreatment is needed for filter paper. Selective analysis methods must be employed to detect the appropriate degradation products from the environmental sample. The described sampling and analysis procedure employs the use of LC/MS because of its versatility, which will aid laboratories with the enhanced capability and capacity to analyze certain environmental matrices for polar CWA degradation products. Gas chromatography-mass spectrometry analysis requires an extra derivatization step, which is often problematic. Although LC-MS analytical methods currently exist for nitrogen mustard degradation products in water, there are no known wipe sampling collection and analysis protocol for the detection of nitrogen mustard degradation products from contaminated surfaces. This report describes experimental details for the research method development and application, by a single laboratory, to assess the recoveries of nitrogen mustard degradation products from porous (vinyl tile, painted drywall, wood) and nonporous (laminate, galvanized steel, glass) surfaces. Performance data (method detection limit and precision and accuracy) are available to demonstrate the fitness-for-purpose towards developing a protocol for nitrogen mustard degradation products in that single laboratory. Analysis of blank samples revealed the presence of TEA and DEA on all tested surfaces, most notably in metal, glass, painted drywall and wood. This was expected given the common commercialization of TEA and DEA in industrial applications (e.g., metal working fluids, soaps, foaming agents, cleaning agents, etc.). Samples are collected from spiked surfaces with wipes and carried through methanol extraction by sonication, filtration, and concentration steps followed by analysis using liquid chromatography electrospray ionization/tandem mass spectrometry (LC/ESI-MS/MS) by direct injection without derivatization. Detection limit data were generated from the application of wipes to a laminate surface, following 40 CFR Part 136, Appendix B, as part of EPA's guidelines for determining a method detection limit. Percent recoveries for the laminate surface were 66-109% for all targeted nitrogen mustard degradation products. The resulting method detection limits obtained from the wipes were 0.12 ng/cm2 for triethanolamine (TEA), 0.06 ng/cm2 for N-ethyldiethanolamine (EDEA), 0.07 ng/cm2 for N-methyldiethanolamine (MDEA), and 0.04 ng/cm2 for diethanolamine (DEA).
Robert Streicher, Ph.D., Project Officer, National Institute for Occupational Safety and Health Laboratories, Alice Hamilton Laboratory, 5555 Ridge Avenue, Cincinnati, OH 45213