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| Titel |
Site selective real-time measurements of atmospheric N2O isotopomers by laser spectroscopy |
| VerfasserIn |
J. Mohn, B. Tuzson, A. Manninen, N. Yoshida, S. Toyoda, W. A. Brand, L. Emmenegger |
| 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 ; 5, no. 7 ; Nr. 5, no. 7 (2012-07-11), S.1601-1609 |
| Datensatznummer |
250003002
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| Publikation (Nr.) |
 copernicus.org/amt-5-1601-2012.pdf |
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| Zusammenfassung |
| We describe the first high precision real-time analysis of the N2O
site-specific isotopic composition at ambient mixing ratios. Our technique
is based on mid-infrared quantum cascade laser absorption spectroscopy
(QCLAS) combined with an automated preconcentration unit. The QCLAS allows
for simultaneous and specific analysis of the three main stable N2O
isotopic species, 14N15N16O, 15N14N16O,
14N14N16O, and the respective site-specific relative isotope
ratio differences δ15Nα and δ
15Nβ. Continuous, stand-alone operation is achieved by using
liquid nitrogen free N2O preconcentration, a quasi-room-temperature
quantum cascade laser (QCL), quantitative sample transfer to the QCLAS and
an optimized calibration algorithm. The N2O site-specific isotopic
composition (δ15Nα and δ15Nβ)
can be analysed with a long-term precision of 0.2‰. The potential of this
analytical tool is illustrated by continuous N2O isotopomer
measurements above a grassland plot over a three week period, which allowed
identification of microbial source and sink processes. |
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