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Determination of Ethylene Oxide at Ultra-Trace Concentrations in Ambient Air Using EPA Method TO-15A: Optimization of VOC Preconcentrator and GC/MS Analytical Method Parameters
Citation:
Cousett, T., K. Oliver, C. Witherspoon, AND A. Whitehill. Determination of Ethylene Oxide at Ultra-Trace Concentrations in Ambient Air Using EPA Method TO-15A: Optimization of VOC Preconcentrator and GC/MS Analytical Method Parameters. Air & Waste Management Association Air Quality Measurements Methods Technology, Durham, NC, November 14 - 16, 2023.
Impact/Purpose:
This research addresses the emergent and ongoing health concerns related to exposure to EtO. Our research is focused on developing sensitive and robust analytical methods necessary for ultra-trace EtO monitoring efforts. These results will shape a forthcoming EtO guidance document which will support the wider ambient air monitoring community and aid community and environmental groups with exposure assessment and monitoring in environmental justice regions.
Description:
The United States Environmental Protection Agency (EPA) Office of Research and Development (ORD) is optimizing preconcentration-based gas chromatography/mass spectrometry (GC/MS) analytical methods for determination of ultra-trace concentrations of ethylene oxide (EtO) in ambient air using EPA Method TO15A (U.S. EPA, 2019). Method TO15A outlines best practices for the determination of Toxic Organic (TO) volatile organic compounds (VOCs) in ambient air at concentrations as low as 20 parts per trillion by volume (pptv) using specially prepared canisters for collection of whole air samples. In response to emergent and ongoing health concerns related to exposure to EtO (U.S. EPA, 2016), we are developing sensitive and robust analytical methods necessary for ultra-trace EtO monitoring efforts. With the ultimate goal of quantifying EtO in ambient air at concentrations as low as 10 pptv, we optimized VOC preconcentration and GC/MS parameters on two different analytical systems. We discuss the method development and results achieved using optimized settings to enhance instrument sensitivity and selectivity. These results will shape a forthcoming EtO guidance document which will support the wider ambient air monitoring community and aid community and environmental groups with exposure assessment and monitoring in environmental justice regions. References: U.S. EPA. 2016. Evaluation of the Inhalation Carcinogenicity of Ethylene Oxide (CASRN 75-21-8) In Support of Summary Information on the Integrated Risk Information System (IRIS), EPA/635/R-16/350Fa. https://cfpub.epa.gov/ncea/iris/iris_documents/documents/toxreviews/1025tr.pdf (last accessed June 15, 2023). U.S. EPA. 2019. Method TO-15A: Determination of Volatile Organic Compounds (VOCs) in Air Collected in Specially Prepared Canisters and Analyzed by Gas Chromatography–Mass Spectrometry (GC-MS). Research Triangle Park, NC: Office of Research and Development, National Exposure Research Laboratory, and Office of Air Quality Planning and Standards, Air Quality Assessment Division. https://www.epa.gov/sites/production/files/2019-12/documents/to-15a_vocs.pdf (last accessed June 15, 2023).