Derivatization Methods for Perfluoroalkyl Substances (PFAS) by Gas Chromatography/Tandem Mass Spectrometry
The perfluoroalkyl substances (PFAS) are environmentally persistent, non-degradable, bioaccumulative, and potentially harmful. These "forever chemicals" are widely distributed across the globe, and methods are needed for the rapid and routine analysis in a variety of matrices. Gas chromatography with mass spectrometry (GC/MS) is commonly used for the analysis of water samples, but PFAS compounds pose special problems in sample pretreatment, separation, and detection. Here, we present our work towards a sensitive, simple, and reliable analytical technique for the determination of perfluorocarboxylic acids (PFCAs) by GC/MS after amidation with 2,4- difluoroaniline (DFA). We report the optimized conditions for the synthesis of the derivatized analytes, as well as their GC retention properties and characteristic mass spectrometric fragments. The overall instrument detection limit is determined from a calibration curve study, and found to be acceptable for the analysis of surface water samples following appropriate solid-phase extraction and derivatization.