Simultaneous targeted and non-targeted analysis of per- and polyfluoroalkyl substances in environmental samples by liquid chromatography-ion mobility-quadrupole time of flight-mass spectrometry and mass defect analysis

Per-and polyfluoroalkyl substances (PFAS) represent a large group of synthetic organic compounds which exhibit unique properties and have been extensively used for consumer and industrial products, result-ing in a widespread presence in the environment. Regulation requiring PFAS monitoring has been im-plemented worldwide due to their potential health and eco-toxicological effects. Tar geted methods are commonly used to monitor between twenty to forty PFAS compounds, representing only a small frac-tion of the number of compounds that may be present. Consequently, there is an increasing interest in complementary non-targeted methods to screen and identify unknown PFAS compounds with the aim to improve knowledge and to generate more accurate models regarding their environmental mobility and persistence. This work details the development of a method that simultaneously provided targeted and non-targeted PFAS analysis. Ultra-high performance liquid chromatography (UHPLC) was coupled to ion mobility-quadrupole time of flight-mass spectrometry (IMS-QTOF-MS) and used to quantify known and screen unknown PFAS in environmental samples collected within the greater Sydney basin (Australia). The method was validated for the quantification of 14 sulfonate-based PFAS, and a non-targeted data analysis workflow was developed using a combination of mass defect analysis with common fragment and neutral loss filtering to identify fluorine-containing species. The optimised method was applied to the environmental samples and enabled the determination of 3-7 compounds from the targeted list and the detection of a further 56-107 untargeted PFAS. This simultaneous analysis reduces the complexity of multiple analyses, and allows for greater interrogation of the full PFAS load in environmental samples. (c) 2021 Elsevier B.V. All rights reserved.

Automated summary

PFAS, a large group of synthetic organic compounds widely used in consumer and industrial products, have become widespread in the environment. Global regulations requiring monitoring of PFAS have been implemented due to their potential health and eco-toxicological effects. Targeted methods monitor a small fraction of PFAS compounds, while there is growing interest in complementary non-targeted methods to screen and identify unknown PFAS compounds.