Mass spectral studies of native and mass‐labeled perfluorooctanesulfonamides

Abstract

This work examines the mass spectra of several environmentally relevant amides, perfluorooctanesulfonamide (FOSA), NMeFOSA, NEtFOSA, and NMe(2)FOSA, under electron ionization conditions. A previous mass spectral study of FOSA and NEtFOSA led the authors to propose possible structures for some of the fragment ions and fragmentation pathways that might explain their formation. In the present communication, further fragment ions are identified for these two compounds and alternative fragmentation pathways proposed. Mass spectral analyses of NMeFOSA and NMe(2)FOSA and of mass-labeled NMeFOSA and NEtFOSA reinforce our conclusions about potential fragmentation pathways for these amides and the fragment ions expected. The mass spectral data presented here will help chemists to identify signals found in a gas chromatographic/mass spectrometric (GC/MS) analysis that stem from these perfluoroalkylsulfonamides.

Discovery of 40 Classes of Per- and Polyfluoroalkyl Substances in Historical Aqueous Film-Forming Foams (AFFFs) and AFFF-Impacted Groundwater

“…Neutral loss of the polar headgroup, either from m / z 483 or the carboxylate/sulfonate in the PFCAs/PFSAs, results in [C n F 2n+1 ] − ions ( m / z 319, 169, and 119), , which are indicative of the fluorinated tail. In ESI + , the appearance of characteristic fragments m / z 440 and 412, corresponding to C 6 F 13 SO 2 NH + CHCH 2 CH 3 and C 6 F 13 SO 2 NH + CH 2 , respectively, indicate perfluoroalkyl sulfonamido compounds, as observed by others. ,, A neutral loss of SO 2 from m / z 412 forms m / z 348, which suggests the presence of a sulfonamide. , Furthermore, m / z 348 has been observed in the ESI + fragmentation of perfluoroalkyl sulfonamido compounds. , D’Agostino and Mabury identified m / z 104 as a fully protonated betaine, which several novel classes of PFASs contain.…”

“…Class 1 contains four homologues (C 3 –C 6 ) as identified by ESI – . The two observed fragments (SI Figure S2; C 6 homologue) at m / z 78 and 398 are characteristic of the fragment and pseudomolecular ion, respectively, of perfluoroalkyl sulfonamides, which suggests a perfluoroalkyl sulfonamide as a base structure. The relative intensity of the [M+2] isotope peak (∼10%) provides additional evidence of two sulfur atoms.…”

“…23,49,50 A neutral loss of SO 2 from m/z 412 forms m/z 348, which suggests the presence of a sulfonamide. 49,51 Furthermore, m/z 348 has been observed in the ESI + fragmentation of perfluoroalkyl sulfonamido compounds. 23,51 D'Agostino and Mabury identified m/z 104 as a fully protonated betaine, 23 which several novel classes of PFASs contain.…”

Predictions of the Fluorine NMR Chemical Shifts of Perfluorinated Carboxylic Acids, CnF2n+1COOH (n = 6−8)

“…The ammonium salt of perfluorooctanoic acid (PFOA) is essential in the manufacturing of fluoropolymers. , However, PFCAs such as perfluorooctanoic acid, PFOA, have recently received much attention as ubiquitous environmental contaminants. − For example, PFOA has been detected in surface water ,, in locations around the world, and the long-chain PFCAs (C n F 2 n +1 −COOH, where n = 9−15) have been detected in some animals from circumpolar regions . The monitoring − and toxicities − of PFCAs have received much recent attention. The 19 F nucleus has advantageous properties for experimental NMR such as 100% natural abundance and spin 1 / 2 .…”

Solid-phase extraction of perfluoroalkylated compounds from sea water

“…The experimental conditions for the determination of the seven PFCAs by LC-MS/MS were based on our previous work [24]. However, different MRM transitions were selected for PFOS since the typical MRM transition, from the molecular anion [M-H]to the product ions m/z 80 ([SO 3 ] − ) and m/z 99 ([SO 3 F] − ), frequently used in the literature [25] had low intensity in our instrument. This can be attributed to a poor transmission efficiency for low masses in our LC-MS/MS system, already detected for other analytes [26].…”