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| Titel |
A chemical analyzer for charged ultrafine particles |
| VerfasserIn |
S. G. Gonser, A. Held |
| 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 ; 6, no. 9 ; Nr. 6, no. 9 (2013-09-11), S.2339-2348 |
| Datensatznummer |
250085059
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| Publikation (Nr.) |
 copernicus.org/amt-6-2339-2013.pdf |
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| Zusammenfassung |
| New particle formation is a frequent phenomenon in the atmosphere and of
major significance for the Earth's climate and human health. To date the
mechanisms leading to the nucleation of particles as well as to aerosol
growth are not completely understood. A lack of appropriate measurement
equipment for online analysis of the chemical composition of freshly
nucleated particles is one major limitation. We have developed a Chemical
Analyzer for Charged Ultrafine Particles (CAChUP) capable of analyzing
particles with diameters below 30 nm. A bulk of size-separated particles is
collected electrostatically on a metal filament, resistively desorbed and
subsequently analyzed for its molecular composition in a time of flight mass
spectrometer. We report on technical details as well as characterization
experiments performed with the CAChUP. Our instrument was tested in the
laboratory for its detection performance as well as for its collection and
desorption capabilities. The manual application of defined masses of camphene
(C10H16) to the desorption filament resulted in a detection limit
between 0.5 and 5 ng, and showed a linear response of the mass spectrometer.
Flow tube experiments of 25 nm diameter secondary organic aerosol from
ozonolysis of alpha-pinene also showed a linear relation between collection
time and the mass spectrometer's signal intensity. The resulting mass spectra
from the collection experiments are in good agreement with published work on
particles generated by the ozonolysis of alpha-pinene. A sensitivity study
shows that the current setup of CAChUP is ready for laboratory measurements
and for the observation of new particle formation events in the field. |
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