Using mass defect plots as a discovery tool to identify novel fluoropolymer thermal decomposition products

Abstract

Fire events involving halogenated materials, such as plastics and electronics, produce complex mixtures that include unidentified toxic and environmentally persistent contaminants. Ultrahigh-resolution mass spectrometry and mass defect filtering can facilitate compound identification within these complex mixtures. In this study, thermal decomposition products of polychlorotrifluoroethylene (PCTFE, [-CClF-CF2 -]n), a common commercial polymer, were analyzed by Fourier transform ion cyclotron resonance mass spectrometry. Using the mass defect plot as a guide, novel PCTFE thermal decomposition products were identified, including 29 perhalogenated carboxylic acid (PXCA, X = Cl,F) congener classes and 21 chlorine/fluorine substituted polycyclic aromatic hydrocarbon (X-PAH, X = Cl,F) congener classes. This study showcases the complexity of fluoropolymer thermal decomposition and the potential of mass defect filtering to characterize complex environmental samples.

Strategies for grouping per- and polyfluoroalkyl substances (PFAS) to protect human and environmental health

“…PFOA), which are widely distributed in the Asian environment 54 and can undergo long-range global transport, 55,56 (ii) there are concerns among scientists and regulators regarding the substitute processing aids used (e.g. HFPO-DA is now an SVHC under the EU REACH regulation), 15 (iii) a wide range of potentially hazardous byproducts have been observed in the environment near uoropolymer manufacturing sites, 14,57,58 (iv) environmental emissions of these persistent polymers during use and at end of life are problematic given the current concern regarding persistent microplastics in the environment (even if uoropolymer plastic waste is of relatively low volume), 59 and (v) the best available technology for treatment of solid wastes is currently incineration, from which emissions of harmful chemicals including certain PFAS could occur if incineration is not operated according to international guidelines. 60 The PLC criteria should be applied on a product-by-product basis because individual uoropolymer products (e.g.…”

Toward Comprehensive Per- and Polyfluoroalkyl Substances Annotation Using FluoroMatch Software and Intelligent High-Resolution Tandem Mass Spectrometry Acquisition

“…FluoroMatch Modular can be used to annotate feature tables generated by any approach (for example, XCMS or vendor software such as Compound Discoverer), and hence, annotations can be appended after prior non-targeted steps including selecting homologue features using mass defect plots. [13][14][15][16][17] The modular version supports any vendor; specific methods and conversion parameters are provided in the manual for Waters and Bruker's files, along with the previous three vendors mentioned. FluoroMatch consists of FluoroMatch Flow (covering the entire workflow from file conversion to annotation), FluoroMatch Modular (covering only annotation, which can be integrated with upstream data-processing workflows), and FluoroMatch Generator (for developing new PFAS in-silico libraries).…”

“…Mass defects calculated using fluorine-containing repeating units (e.g., CF 2 ) instead of 12 C, can be plotted against nominal mass to determine homologous series of PFAS subclasses. [13][14][15][16][17] The success of this approach as annotation based solely on exact mass hinges on the assumption that most polyfluorinated compounds occupy a region of compositional space 18 that is devoid of other non-halogenated chemicals. An analysis of the PubChem library as well as inventories of high production volume chemicals (e.g., the US Toxic Substances Control Act's Chemical Substance Inventory) 19 show that this assumption is not true.…”

Aerobic biodegradation of 2 fluorotelomer sulfonamide–based aqueous film–forming foam components produces perfluoroalkyl carboxylates

“…External calibration of the MS was performed using 10 times diluted Agilent Tune Mix for Ion Traps in ESIþ and a mixture of PFCAs and fluorotelomer phosphate diesters described previously in ESI- [8]. Plotting the mass spectra as mass defect plots on a CF 2 scale as described by Myers et al [23], with the exception that nominal masses were determined by standard rounding rather than automatically rounding down, assisted in the identification of PFAS ions of interest based on their mass defects. Further details of the qTOF-MS settings and analysis of qTOF-MS data are provided in the Supplemental Data.…”