Chemical ionization pathways of polyfluorinated chemicals—A connection to environmental atmospheric processes

Abstract

A systematic mass spectrometry study of an industrially prolific class of polyfluorinated compounds known as telomers was conducted. The study specifically focused upon polyfluorinated alcohols along with corresponding saturated and ␣,␤-unsaturated fluoroacids. Within each class differing fluoroalkyl chain length homologues were investigated, using negative and positive chemical ionization mass spectrometry (NCI and PCI). In the case of the fluoroalcohols, NCI resulted in the production of more elaborate spectra than the other classes. Moreover, it showed the interesting production of HF 2 Ϫ and the complex of this species, along with F Ϫ , with the parent molecule. These complexes resulted in the formation of the novel H 2 F 3 Ϫ ion. Results show that there is significant intra-molecular hydrogen bonding that occurs for these compounds, which influences the molecules fragmentation. This bonding will also influence the fate and disposition through environmental processes (e.g., V P , k OH , K OW , K OA ) which are affected by molecular geometry. Furthermore, there is an increased accumulation and persistence potential for the molecule as a function of the fluorocarbon chain length. We have shown that in conjunction with the use of mass spectroscopy the engertics of environmental processes for polyfluorinated materials can be

Using COSMOtherm to predict physicochemical properties of poly- and perfluorinated alkyl substances (PFASs)

“…In agreement with previous studies, [21,28,29] we found several energetically stable conformers for FTOHs. These belong to two groups: stretched conformations (SCs) and conformations with an intramolecular hydrogen bond between the hydroxylic proton and fluorine attached to the C 3 carbon (electrostatically interacting conformations, EICs), Fig.…”

Perfluoroalkyl Compounds

“…A similar intramolecular hydrogen bond can also exist in NMeFOSE and NEtFOSE [61]. This intramolecular hydrogen bonding influences the geometry of the molecule and, as such, may also influence physical properties such as vapour pressure and octanol-water or octanol-air partitioning coefficients [58,59].…”

“…Depending on the hydrophilic end group of the PFC, hydrogen bonding between the end group and the perfluoroalkyl chain can occur [53,[56][57][58][59][60]. For example, in the FTOHs, an intramolecular hydrogen bond can exist between the hydroxylic proton and the two fluorine atoms next to the ethanol moiety (ÀOÀH ... FÀ) [58,59].…”

“…For example, in the FTOHs, an intramolecular hydrogen bond can exist between the hydroxylic proton and the two fluorine atoms next to the ethanol moiety (ÀOÀH ... FÀ) [58,59]. A similar intramolecular hydrogen bond can also exist in NMeFOSE and NEtFOSE [61].…”

Perfluorobutyric Acid and Its Monohydrate: A Chirped Pulse and Cavity Based Fourier Transform Microwave Spectroscopic Study

“…Ellis et al investigated a series of PFCAs by 19 F NMR techniques. [7] They found that the polyfluorinated chains adopt a helical-twist geometry, whereas their hydrocarbon counterparts prefer a "zigzag" geometry. Altarawneh [8] examined the potential-energy surface for the self-decomposition of PFBA theoretically.…”