Chemical Ionization Mass Spectrometry for Real-time Monitoring of Semivolatile Emerging Atmospheric Contaminants: Application of the AIM Reactor in PFAS Detection

Per- and Polyfluoroalkyl Substances (PFAS) in the Environment
Oral Presentation

Prepared by V. Pospisilova1, S. Jorga2, O. El Hajj2, A. Koss2
1 - Tofwerk, General Guisanstrasse, 39, Spiez, Bern, 3700, Switzerland
2 - Tofwerk, , , United States


Contact Information: [email protected]; +41786461816

ABSTRACT

Per- and polyfluoroalkyl substances (PFAS) are a diverse group of anthropogenic contaminants widely recognized for their environmental and health implications. Their widespread use in manufacturing, coupled with the toxicity of certain PFAS classes, has led to their high concentration detection in various environmental mediums and human blood serum, raising public health concerns [1]. The adverse health effects linked to PFAS exposure necessitate urgent research and regulatory action. However, the understanding of PFAS environmental behavior and degradation is limited due to traditional offline analytical methods lacking necessary temporal resolution. Time-of-flight chemical ionization mass spectrometry (ToF-CIMS) offers an effective solution for measuring atmospherically relevant PFAS classes in the gas-phase. It provides high time-resolution measurements with sub part-per-trillion (ppt) detection limits. Recent studies have validated the capabilities of ToF-CIMS in detecting diverse PFAS classes at sub part-per-trillion (ppt) levels, supporting its potential in advancing PFAS research [2,3].
Here, we report measurements of key atmospheric PFAS classes, particularly perfluoroalkyl carboxylic acids (PFCAs) and fluorotelomer alcohols (FTOHs), using our newly developed AIM chemical ionization reactor. The AIM reactor is tailored for adduct-ion chemistry, enabling the analysis of complex, less volatile molecules with minimal fragmentation. Our study emphasizes developing a robust calibration method, examining sensitivity under different sampling conditions, and evaluating the use of various reagent ions. By employing iodide as the ion-adduct, we conducted a detailed sensitivity analysis for 2 FTOHs and 11 PFCAs. The results demonstrate normalized sensitivities that span from 1 to 9 ncps/ppt, along with achieving a detection limit as low as 1 ppt.
This study highlights the AIM reactor's versatility as a tool for ambient measurements, encompassing a range of emerging contaminants beyond typical VOCs and inorganic acids at sub-ppt levels. Its high selectivity, achieved through multiple reagent ions, underscores its significant potential in environmental monitoring. The real time detection of PFAS and other emerging contaminatns in air opens new possibilities for their accurate tracing and control of emission sources ensuring fast intervention and thus protection of the environment and public health.



[1] A. O. De Silva et al., “PFAS exposure pathways for humans and wildlife: a synthesis of current knowledge and key gaps in understanding,” Environ. Toxicol. Chem., vol. 40, no. 3, pp. 631–657, 2021.
[2] B. B. Bowers, J. A. Thornton, and R. C. Sullivan, “Evaluation of iodide chemical ionization mass spectrometry for gas and aerosol-phase per-and polyfluoroalkyl substances (PFAS) analysis,” Environ. Sci. Process. Impacts, vol. 25, no. 2, pp. 277–287, 2023.
[3] T. P. Riedel, J. R. Lang, M. J. Strynar, A. B. Lindstrom, and J. H. Offenberg, “Gas-phase detection of fluorotelomer alcohols and other oxygenated per-and polyfluoroalkyl substances by chemical ionization mass spectrometry,” Environ. Sci. Technol. Lett., vol. 6, no. 5, pp. 289–293, 2019.