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Technical University of Crete
Technical University of Crete
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| URI | http://purl.tuc.gr/dl/dias/10879274-4BE4-42A0-B396-51B61788C939 | - |
| Identifier | https://doi.org/10.1021/jp9051352 | - |
| Identifier | https://pubs.acs.org/doi/abs/10.1021/jp9051352 | - |
| Language | en | - |
| Extent | 4 pages | en |
| Title | Acid dissociation versus molecular association of perfluoroalkyl oxoacids: environmental implications | en |
| Creator | Psyllaki Eleftheria | en |
| Creator | Ψυλλακη Ελευθερια | el |
| Creator | Cheng Jie | en |
| Creator | Colussi Arthur, Gabriella, 1957- | en |
| Creator | Hoffmann M. R. | en |
| Publisher | ACS | en |
| Publisher | American Chemical Society | en |
| Content Summary | Perfluorooctanoate (PFO) and perfluorooctanesulfonate (PFOS) surfactant anions, once released, may rapidly reach remote regions. This phenomenon is puzzling because the water-bound anions of strong F-alkyl acids should be largely transported by slow oceanic currents. Herein, we investigate whether these hydrophobic F-alkyl oxoanions would behave anomalously under environmental conditions, as suggested elsewhere. Negative electrospray ionization mass spectra of micromolar aqueous PFO or PFOS solutions from pH 1.0 to 6.0 show (1) m/z ) 499 (PFOS) signals that are independent of pH and (2) m/z ) 413 (PFO) and 369 (PFO - CO2) signals, plus m/z ) 213 (C F CO -) and 169 (C F -) signals at higher collision energies, and, below pH ∼ 372 37 4, m/z ) 827 signals from a remarkably stable (PFO)2H- cluster that increase with decreasing pH. Since the sum of the m/z ) 369, 413, and 827 signal intensities is independent of pH, that is, effectively encompasses all major species, we infer that pKa(PFOSA) < 1.0 and pKa(PFOA) < 1.0. We also derive K2 e 4 × 107 M-2 for the clustering equilibrium 2PFO + H+ h (PFO)2H. Thus, although (PFO)2H is held together by an exceptionally strong homonuclear covalent hydrogen bond, neither PFOS nor PFO will associate or protonate significantly at environmentally relevant subnanomolar concentrations above pH ∼ 1. | en |
| Type of Item | Peer-Reviewed Journal Publication | en |
| Type of Item | Δημοσίευση σε Περιοδικό με Κριτές | el |
| License | http://creativecommons.org/licenses/by/4.0/ | en |
| Date of Item | 2015-09-24 | - |
| Date of Publication | 2009 | - |
| Subject | Perfluoroalkyl oxoacids | en |
| Bibliographic Citation | J .Cheng, E. Psillakis, M. R. Hoffmann and A. J. Colussi , "Acid dissociation versus molecular association of perfluoroalkyl oxoacids: environmental implications", J. Phys. Chem. A, vol.113, no. 29, pp.8152–8156, Jul. 2009. doi: 10.1021/jp9051352 | en |
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