Zheng Yufang, Erisman Edward P, Ji Weihua, Stein Stephen E, Wallace William E
Mass Spectrometry Data Center, Biomolecular Measurement Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States.
J Am Soc Mass Spectrom. 2025 Sep 3;36(9):1970-1978. doi: 10.1021/jasms.5c00185. Epub 2025 Aug 11.
Per- and polyfluoroalkyl substances (PFAS) are environmentally persistent compounds that present analytical challenges due to their stability and low concentrations. In this study, electron ionization (EI) mass spectra of trimethylsilyl (TMS) derivatized fluorinated alcohols and carboxylic acids were examined to improve PFAS identification in the NIST Mass Spectral Reference Library. In contrast with the spectra of unsubstituted alcohol TMS compounds featuring losses of hydrocarbons, fluorinated alcohol TMS derivatives are characterized by the losses of fluorinated silyl groups. For example, a previously unreported [M-111] ion was consistently observed in compounds containing three methylene groups between the hydroxyl group and the first CF unit. Detailed quality assurance analysis using a suite of NIST software tools along with high-resolution TOF-MS confirmed the origin and elemental composition of these ions. MS experiments and full scan of TMS derivatives of fluorinated alcohols with varying numbers of methylene groups investigations suggest the formation of a five-membered ring intermediate as a key feature in this unique fragmentation pathway. These findings improve our understanding of PFAS fragmentation and support more accurate compound identification in analytical workflows.
全氟和多氟烷基物质（PFAS）是环境持久性化合物，由于其稳定性和低浓度，在分析方面存在挑战。在本研究中，对三甲基硅烷基（TMS）衍生的氟化醇和羧酸的电子电离（EI）质谱进行了研究，以改进美国国家标准与技术研究院（NIST）质谱参考库中PFAS的鉴定。与以烃类损失为特征的未取代醇TMS化合物的光谱不同，氟化醇TMS衍生物的特征是氟化硅烷基的损失。例如，在羟基与第一个CF单元之间含有三个亚甲基的化合物中，始终观察到一个以前未报道的[M-111]离子。使用一套NIST软件工具以及高分辨率飞行时间质谱（TOF-MS）进行的详细质量保证分析证实了这些离子的来源和元素组成。对具有不同亚甲基数量的氟化醇TMS衍生物进行的质谱实验和全扫描研究表明，五元环中间体的形成是这一独特裂解途径的关键特征。这些发现增进了我们对PFAS裂解的理解，并支持在分析工作流程中更准确地鉴定化合物。
