Rapid Characterization of Emerging Per- and Polyfluoroalkyl Substances in Aqueous Film-Forming Foams Using Ion Mobility Spectrometry–Mass Spectrometry

Aqueous film-forming foams (AFFF) are mixtures formulated with numerous hydrocarbon- and fluoro-containing surfactants. AFFF use leads to environmental releases of unknown per- and polyfluoroalkyl substances (PFAS). AFFF composition is seldom disclosed, and their use elicits concerns from both regulatory agencies and the public because PFAS are persistent in the environment and potentially associated with adverse health effects. In this study, we demonstrate the use of coupled liquid chromatography, ion mobility spectrometry, and mass spectrometry (LC-IMS-MS) to rapidly characterize both known and unknown PFAS in AFFF. Ten AFFF formulations from seven brands were analyzed using LC-IMS-MS in both negative and positive ion modes. Untargeted analysis of the formulations was followed by feature identification of PFAS-like features utilizing database matching, mass defect and homologous series evaluation, and MS/MS fragmentation experiments. Across the tested AFFF formulations, we identified 33 homologous series; only ten of these homologous series have been previously reported. Among tested AFFF, the FireStopper (n = 85) contained the greatest number of PFAS-like features and Phos-Check contained zero. This work demonstrates that LC-IMS-MS-enabled untargeted analysis of complex formulations, followed by feature identification using data-processing algorithms, can be used for rapid exposure characterization of known and putative PFAS during fire suppression-related contamination events.水成膜泡沫灭火剂（Aqueous film-forming foams, AFFF）是由多种含烃类与含氟表面活性剂复配而成的混合物。该类灭火剂的使用会导致环境中释放出未被鉴定的全氟和多氟烷基物质（per- and polyfluoroalkyl substances, PFAS）。水成膜泡沫灭火剂的配方极少对外公开，其使用引发了监管机构与公众的双重担忧：全氟和多氟烷基物质在环境中具有持久性，且可能与不良健康效应存在关联。本研究中，我们展示了联用液相色谱-离子迁移谱-质谱（liquid chromatography, ion mobility spectrometry, and mass spectrometry, LC-IMS-MS）技术，可快速表征水成膜泡沫灭火剂中已知与未知的全氟和多氟烷基物质。我们采用正负两种离子模式，通过LC-IMS-MS分析了7个品牌的10种水成膜泡沫灭火剂配方。对这些配方开展非靶向分析后，我们通过数据库匹配、质量缺陷与同系物评估以及串联质谱（MS/MS）碎裂实验，完成了类PFAS特征的识别。在所测试的水成膜泡沫灭火剂配方中，我们共识别出33个同系物系列，其中仅10个曾被既往研究报道。在所测试的样品中，FireStopper（n=85）所含类PFAS特征数量最多，而Phos-Check未检出任何此类特征。本研究证明，借助LC-IMS-MS对复杂配方开展非靶向分析，再结合数据处理算法完成特征识别，可用于快速表征与灭火相关污染事件中已知及推定存在的全氟和多氟烷基物质暴露情况。