Leveraging the High-Resolution Time-of-Flight Aerosol Mass Spectrometer to Measure PFAS Aerosols

Per- and Polyfluoroalkyl Substances (PFAS) represent an emerging class of pollutants found in various media across the environment. This wide array of nearly 15,000 compounds varies in volatility and solubility. As such, PFAS can be present in both the gas-phase and particle-phase within the atmosphere, or even dissolved within wet aerosols and cloud droplets. The High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) is a widely used instrument for analysis of atmospheric aerosol chemistry, but is not typically used to detect trace PFAS compounds in the atmosphere. To assess the feasibility of measuring PFAS aerosols with the HR-ToF-AMS, we utilized the 3D-printed PRIZE (PRinted fluidIZed bed gEnerator) for dry dispersion of commercially obtained nanospheres of PTFE (polytetrafluoroethylene, [C­­₂F₄]_n, D̅_p ≈ 100nm). Clear evidence of C_nF_m fragments were detected, indicating efficient volatilization and ionization of PTFE within the HR-ToF-AMS. We quantify the detection efficiency of PTFE particles within the HR-ToF-AMS by comparing to parallel measurements with a Scanning Mobility Particle Sizer (SMPS). We subsequently examine HR-ToF-AMS data collected at landfills in New York State from a 2021 field project for which methane emissions were previously assessed, to see if trace concentrations of PFAS can be detected in these ambient air quality samples.