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| Titel |
Enrichment Factors of Perfluoroalkyl Anionic Surfactants at the Air/water Interface |
| VerfasserIn |
M. R. Hoffmann, A. J. Colussi, J. Cheng |
| Konferenz |
EGU General Assembly 2009
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250029108
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| Zusammenfassung |
| The refractory, water-bound perfluoro-n-alkyl carboxylate (n-PFC-) and sulfonate (n- PFS-)
surfactants reach remote locations hydrologically unconnected to their sources via hitherto
unknown processes. Here we quantify the enrichment of these anions in microdroplets
produced by aerosolization of 1 μM aqueous surfactant solutions at pH 7 using sonic spray
ionization mass spectrometry. Relative enrichment factors fsteeply increase from n= 1 to 3,
level off at f(n-PFS-) ~ 2.3 f(n-PFC-) ~ 190 f(Br-) (n -¥ 8), and display even-odd effects.
The preferential enrichment of n-PFS- over n-PFC- reflects a larger headgroup. The
hyperbolic, rather than the predicted linear ln fvs. ndependence suggests the onset of
conformational restrictions to interfacial enrichment above n ~ 3. Marine aerosols produced
from contaminated ocean surface waters are thus expected to be highly enriched in
PFC-s/PFS-s. The monotonic accumulation of 8-PFS- and PFC-s in East and, less
pronouncedly, in West Greenland biomarkers is therefore consistent with the deposition
of marine aerosol drawn from contaminated North American Current waters and
transported westward by predominant easterlies. The analogous trend for PFC-s
in Canadian Arctic biota vis-a-vis the rapid decline of 8-PFS- after 2000 suggest
that the fresher Labrador Sea does not sustain a similar process over this region. |
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