Grantee Research Project Results
2023 Progress Report: Development of High-Resolution Chemical Ionization Mass Spectrometry Methods for Real-Time Measurement of Emerging Airborne Per- and Polyfluoroalkyl Substances (PFASs)
EPA Grant Number: R840431Title: Development of High-Resolution Chemical Ionization Mass Spectrometry Methods for Real-Time Measurement of Emerging Airborne Per- and Polyfluoroalkyl Substances (PFASs)
Investigators: Surratt, Jason D. , Zhang, Yue , Turpin, Barbara J , Brooks, Sarah D , Zhang, Zhenfa
Institution: University of North Carolina at Chapel Hill , Texas A & M University
EPA Project Officer: Chung, Serena
Project Period: May 1, 2022 through April 30, 2025 (Extended to April 30, 2026)
Project Period Covered by this Report: May 1, 2023 through April 30,2024
Project Amount: $799,833
RFA: Measurement and Monitoring Methods for Air Toxics and Contaminants of Emerging Concern in the Atmosphere (2021) RFA Text | Recipients Lists
Research Category: PFAS Detection , Air Quality and Air Toxics
Objective:
Our overarching hypothesis for this study is that high-resolution chemical ionization time-of-flight mass spectrometers (HR-ToF-CIMS) using iodide (I-), nitrate (NO3-), hydronium (H3O+), or nitrosyl (NO+) reagent ions can efficiently measure airborne PFASs in real-time down to parts per trillion or even sub-ppt levels. To address this hypothesis, we have 3 major objectives,including: (1) determine HR-ToF-CIMS calibration curves and detection limits for atmosphericallyrelevant PFASs by using commercially-available or synthesized standards; (2) oxidize these PFAS standards with hydroxyl radicals (OH)/ozone (O3) in controlled laboratory settings to generate commercially-unavailable PFAS and to also gain insights into their atmospheric transformations/fates; and (3) deploy a mobile laboratory with these newly developed/lab-validated CIMS methods and other air- and particle-phase sampling techniques at a stationary point source to study fugitive PFAS emissions and their near-source downwind chemistry.
Progress Summary:
- We developed a quantitative method for real-time analysis of gas-phase fluorotelomer alcohols (FTOHs), perfluoroalkyl acids (PFCAs and GenX), one perfluorooctane sulfonamide (EtFOSA), one fluorotelomer diol (FTdiOH), and one fluorinated ether (E2) using high-resolution time-of-flight chemical ionization mass spectrometry equipped with iodide reagent ion chemistry (I-HR-ToFCIMS) (Davern et al., 2024, Analyst). In this published work, we present a direct liquid injection method for external calibration of PFAS for I-HR-ToF-CIMS.
- We applied our developed I-HR-ToF-CIMS method to measure emission rates from new/old rain jackets (Eichler et al., 2024, Indoor Environments, pending acceptance), which demonstrated the need of considering consumer products as sources of indoor air exposure to PFAS.
- We used Vocus-CIMS to optimize NO+ reagent ion chemistry for real-time measurement of PFAS compounds in positive ion mode, achieving ppt level of detection limit for four previously unreported classes of PFAS compounds not measurable by I-HR-ToF-CIMS, including: fluorinated olefins (FO), hydrofluoroalkanes (HF alkanes), fluorinated vinyl ethers (FVE), and fluorotelomer acrylates (FTAcr). FVE are especially relevant to Chemours in Fayetteville, NC.
- Oxidation experiments using the PAM reactor have begun, with a special emphasis on vinyl ethers relevant to Chemours in Fayetteville, NC.
- The TAMU team has conducted additional pilot measurements using the mobile lab near Chemours in Corpus Christi, TX, and has been integrating the I-HR-ToF-CIMS from UNC to the TAMU mobile lab.
Future Activities:
- PFAS compounds relevant to Chemours in Fayetteville, NC, such as Nafion byproduct 1, perfluoroolefin, vinyl ethers, and acrylates, will be calibrated in NO+ mode and compared with PTR mode and O2+ mode.
- We will finish calibrating all of the available PFAS standards using HR-ToF-CIMS using O2-, especially since this can be a switchable ion chemistry with I- during our field deployment.
- The degradation of PFAS compounds will be studied in our PAM reactor by using both I- and NO+ modes in HR-ToF-CIMS, aiding in the identification potential oxidation products that can serve as chemical markers for targeted PFAS compounds during our field measurements in winter 2025.
- Field deployment of the mobile laboratory in winter 2025 will have both the UNC and TAMU CIMS instruments operating with I- and NO+ chemistries, respectively.
Journal Articles on this Report : 2 Displayed | Download in RIS Format
| Other project views: | All 16 publications | 3 publications in selected types | All 3 journal articles |
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Davern MJ, West GV, Eichler CMA, Turpin BJ, Zhang Y, Surratt JD. External liquid calibration method for iodide chemical ionization mass spectrometry enables quantification of gas-phase per-and polyfluoroalkyl substances (PFAS) dynamics in indoor air. Analyst. 2024;149(12):3405-15. |
R840431 (2023) R840431 (2024) |
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Eichler CMA, Davern MJ, Surratt JD, Morrison GC, Turpin BJ. Fluorotelomer alcohol (FTOH) emission rates from new and old rain jackets to air determined by iodide high-resolution chemical ionization mass spectrometry. Indoor Environments. 2024;1(4):100055. |
R840431 (2023) R840431 (2024) |
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Supplemental Keywords:
GenX, PFOS, PFOA, organic fluorine, environmental chemistry, analytical chemistry methods, southeast U.S., North Carolina (NC), fine particulate matter (PM2.5), atmospheric chemistry, air pollution, and EPA Region 4Relevant Websites:
Jason D. Surratt, PhD Exit
Department of Atmospheric Sciences Exit
Barbara J. Turpin, PhD Exit
Progress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.