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Copyright Copernicus GmbH 2012

Abstract

We describe the first high precision real-time analysis of the N2 O 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 N2 O isotopic species, 14 N15 N16 O, 15 N14 N16 O, 14 N14 N16 O, and the respective site-specific relative isotope ratio differences δ15 Nα and δ 15 Nβ . Continuous, stand-alone operation is achieved by using liquid nitrogen free N2 O preconcentration, a quasi-room-temperature quantum cascade laser (QCL), quantitative sample transfer to the QCLAS and an optimized calibration algorithm. The N2 O site-specific isotopic composition (δ15 Nα and δ15 Nβ ) can be analysed with a long-term precision of 0.2[per thousand]. The potential of this analytical tool is illustrated by continuous N2 O isotopomer measurements above a grassland plot over a three week period, which allowed identification of microbial source and sink processes.

Details

Title
Site selective real-time measurements of atmospheric N2O isotopomers by laser spectroscopy
Author
Mohn, J.; Tuzson, B.; Manninen, A.; Yoshida, N.; Toyoda, S.; Brand, W. A.; Emmenegger, L.
First page
1601
Publication year
2012
Publication date
2012
Publisher
Copernicus GmbH
ISSN
18671381
e-ISSN
18678548
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
1030944651
Copyright
Copyright Copernicus GmbH 2012