A method to measure total gaseous fluorine

Total fluorine (TF) analysis is a powerful tool for the characterization of organofluorine contaminants in the environment. Organofluorine compounds are known primarily with respect to the notorious subgroup of poly- and perfluoroalkyl substances (PFAS) and as potent greenhouse gases that can impact climate. The use of targeted methods for every organofluorine compound in the environment is not feasible. While methods are available for TF analysis of condensed phase samples, no technique exists for gas phase TF measurements (TFg). Herein we demonstrate an in-situ instrumental method for TFg via platinum catalyzed thermolysis at 1000 °C in the presence of propane. TFg is fully converted into HF and subsequently quan-tified by existing techniques for F-. The method was validated using nine organofluorine compounds with differing functional groups. We characterized TFg and compared to common speciated measurements in the headspace of four commercial fluorosurfactants and outdoor air. Most TFg (65%-99.8%) in the fluoro-surfactant headspace was unknown. In outdoor air, >50% of TFg was unknown. These high quantities of unknown organofluorine indicate a measurement gap in the gas phase, which could have important impli-cations for atmospheric sources and burdens of PFAS and fluorinated greenhouse gases.