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| Titel |
Measuring long chain alkanes in diesel engine exhaust by thermal desorption PTR-MS |
| VerfasserIn |
M. H. Erickson, M. Gueneron, B. T. Jobson |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1867-1381
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Measurement Techniques ; 7, no. 1 ; Nr. 7, no. 1 (2014-01-27), S.225-239 |
| Datensatznummer |
250115569
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| Publikation (Nr.) |
 copernicus.org/amt-7-225-2014.pdf |
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| Zusammenfassung |
| A method using thermal desorption sampling and analysis by proton transfer reaction mass spectrometry (PTR-MS) to measure
long chain alkanes (C12–C18) and other larger organics associated
with diesel engine exhaust emissions is described. Long chain alkanes undergo
dissociative proton transfer reactions forming a series of fragment ions with
formula CnH2n+1. The PTR-MS is insensitive to n-alkanes less than
C8 but displays an increasing sensitivity for larger alkanes. Fragment
ion distribution and sensitivity is a function of drift conditions. At 80 Td
the most abundant ion fragments from C10 to C16 n-alkanes were
m/z 57, 71 and 85. The mass spectrum of gasoline and diesel fuel at 80 Td
displayed ion group patterns that can be related to known fuel constituents,
such as alkanes, alkylbenzenes and cycloalkanes, and other compound groups
that are inferred from molecular weight distributions such as
dihydronapthalenes and naphthenic monoaromatics. It is shown that thermal
desorption sampling of gasoline and diesel engine exhausts at 80 Td allows
for discrimination against volatile organic compounds, allowing for
quantification of long chain alkanes from the abundance of CnH2n+1
fragment ions. The total abundance of long chain alkanes in diesel engine
exhaust was measured to be similar to the total abundance of C1–C4
alkylbenzene compounds. The abundance patterns of compounds determined by
thermal desorption sampling may allow for emission profiles to be developed
to better quantify the relative contributions of diesel and gasoline exhaust
emissions on organic compounds concentrations in urban air. |
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