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| Titel |
Hyphenation of a EC / OC thermal–optical carbon analyzer to photo-ionization time-of-flight mass spectrometry: an off-line aerosol mass spectrometric approach for characterization of primary and secondary particulate matter |
| VerfasserIn |
J. Diab, T. Streibel, F. Cavalli, S. C. Lee, H. Saathoff, A. Mamakos, J. C. Chow, L.-W. A. Chen, J. G. Watson, O. Sippula, R. Zimmermann |
| 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 ; 8, no. 8 ; Nr. 8, no. 8 (2015-08-18), S.3337-3353 |
| Datensatznummer |
250116533
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| Publikation (Nr.) |
 copernicus.org/amt-8-3337-2015.pdf |
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| Zusammenfassung |
| Source apportionment and characterization of primary and secondary aerosols
remains a challenging research field. In particular, the organic composition
of primary particles and the formation mechanism of secondary organic
aerosols (SOAs) warrant further investigations. Progress in this field is
strongly connected to the development of novel analytical techniques. In
this study an off-line aerosol mass spectrometric technique based on filter
samples, a hyphenated thermal–optical analyzer photo-ionization time-of-flight mass spectrometer (PI-TOFMS) system, was developed. The approach
extends the capability of the widely used particulate matter (PM) carbon analysis (for
elemental / organic carbon, EC / OC) by enabling the investigation of evolved
gaseous species with soft and selective (resonance enhanced multi-photon ionization, REMPI) and non-selective photo-ionization (single-photon
ionization, SPI) techniques. SPI was tuned to be medium soft to achieve
comparability with results obtained by the electron ionization aerosol mass spectrometer (AMS). Different PM samples including wood combustion
emission samples, smog chamber samples from the reaction of ozone with
different SOA precursors, and ambient samples taken at Ispra, Italy, in
winter as well as in summer were tested. The EC / OC–PI-TOFMS technique
increases the understanding of the processes during thermal–optical
analysis and identifies marker substances for the source apportionment.
Composition of oligomeric or polymeric species present in PM can be
investigated by the analysis of the thermal breakdown products. In the case of
wood combustion, in addition to the well-known markers at m/z ratios of 60
and 73, two new characteristic masses (m/z 70 and 98) have been revealed as
potentially linked to biomass burning. All four masses were also the
dominant signals in an ambient sample taken in winter time in Ispra, Italy,
confirming the finding that wood burning for residential heating is a major
source of PM in winter at this location. The summer
sample from the same location showed no influence of wood burning, but seems
to be dominated by SOAs, which was confirmed from the comparison with chamber
experiment samples. The experiments conducted with terpenes as precursors
showed characteristic masses at m/z 58 and 82, which were not observable in
any other emission samples and could serve as a marker for SOA from terpenes. |
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