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| Titel |
Size distribution of alkyl amines in continental particulate matter and their online detection in the gas and particle phase |
| VerfasserIn |
T. C. VandenBoer, A. Petroff, M. Z. Markovic, J. G. Murphy |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 11, no. 9 ; Nr. 11, no. 9 (2011-05-10), S.4319-4332 |
| Datensatznummer |
250009706
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| Publikation (Nr.) |
 copernicus.org/acp-11-4319-2011.pdf |
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| Zusammenfassung |
| An ion chromatographic method is described for the quantification of the
simple alkyl amines: methylamine (MA), dimethylamine (DMA), trimethylamine
(TMA), ethylamine (EA), diethylamine (DEA) and triethylamine (TEA), in the
ambient atmosphere. Limits of detection (3σ) are in the tens of pmol
range for all of these amines, and good resolution is achieved for all
compounds except for TMA and DEA. The technique was applied to the analysis
of time-integrated samples collected using a micro-orifice uniform
deposition impactor (MOUDI) with ten stages for size resolution of particles
with aerodynamic diameters between 56 nm and 18 μm. In eight samples
from urban and rural continental airmasses, the mass loading of amines
consistently maximized on the stage corresponding to particles with
aerodynamic diameters between 320 and 560 nm. The molar ratio of amines to
ammonium (R3NH+/NH4+) in fine aerosol ranged between
0.005 and 0.2, and maximized for the smallest particle sizes. The
size-dependence of the R3NH+/NH4+ ratio indicates
differences in the relative importance of the processes leading to the
incorporation of amines and ammonia into secondary particles. The technique
was also used to make simultaneous hourly online measurements of amines in
the gas phase and in fine particulate matter using an Ambient Ion Monitor
Ion Chromatograph (AIM-IC). During a ten day campaign in downtown Toronto,
DMA, TMA + DEA, and TEA were observed to range from below detection limit to
2.7 ppt in the gas phase. In the particle phase, MAH+ and TMAH+ +
DEAH+ were observed to range from below detection limit up to 15 ng m−3.
The presence of detectable levels of amines in the particle phase
corresponded to periods with higher relative humidity and higher mass
loadings of nitrate. While the hourly measurements made using the AIM-IC
provide data that can be used to evaluate the application of gas-particle
partitioning models to amines, the strong size-dependence of the
R3NH+/NH4+ ratio indicates that using bulk measurements
may not be appropriate. |
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