Fluorination Using PFAS Reagents Generated by Mass Spectrometry

We report tandem mass spectrometry (MS/MS) experiments using a modified commercial quadrupole ion trap (QIT) mass spectrometer in which perfluoroalkyl and polyfluoroalkyl substances (PFAS) are fragmented to yield difluorocarbene, a neutral reagent that is then reacted in situ with trapped ions. Reactions with ionized hydroxy acids, phenols, and a lipid are demonstrated. Lipid double bond localization and isomer quantitation are shown through collision-induced dissociation (CID) and the measurement of ion-molecule reaction kinetics obtained from a single injection of reagent ions and multiple ejections of product ions as a function of time. The implications and theoretical aspects of this chemistry are discussed.