 |
| Titel |
Laser spectroscopic analysis of ambient N2O isotopomers for source identification |
| VerfasserIn |
Joachim Mohn, Béla Tuzson, Pascal Wunderlin, Jan Reent Köster, Albert Manninen, Lukas Emmenegger |
| Konferenz |
EGU General Assembly 2011
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250054153
|
|
|
|
|
|
| Zusammenfassung |
| The intramolecular distribution of 15N in N2O can be used to obtain important information on the geochemical cycle of N2O because many biological and chemical processes have distinct isotopic signatures. N2O is a linear, non-symmetric molecule (N–N–O), with one nitrogen atom at the center (a site) and one at the end (b site). Therefore, one can distinguish between two structural isomers containing one heavy isotope of nitrogen, namely 14N15N16O and 15N14N16O, referred to as 15Na and 15Nb, respectively.
Employing recently available quantum cascade lasers (QCL) we are able to perform continuous and precise analysis (0.1 per mille) of the site-specific isotopic ratios d15Na and d15Nb of N2O [1]. Coupling the QCL spectrometer to a specifically engineered liquid nitrogen free and fully-automated preconcentration unit we achieve quasi-continuous and high precision analysis of N2O isotopomers at ambient concentrations [2].
Results from recent measurement campaigns will be presented ranging from continuous analysis of N2O isotopomers (1 Hz) at elevated concentrations in soil and wastewater incubation experiments to ambient air monitoring of N2O isotopic ratios. Incubation experiments under controlled conditions were performed to determine the site-specific isotopic signatures of distinct N2O source and sink processes. These source signatures in combination with ambient N2O isotopomer time series can then be employed for source allocation and partitioning on a local, regional or even global scale.
[1] Wächter, H., Mohn, J., Tuzson, B., Emmenegger, L., and Sigrist, M. W.: Determination of N2O isotopomers with quantum cascade laser based absorption spectroscopy, Opt. Express, 16, 9239–9244, 2008.
[2] Mohn, J., Guggenheim, C., Tuzson, B., Vollmer, M. K., Toyoda, S., Yoshida, N. and Emmenegger, L., A liquid nitrogen-free preconcentration unit for measurements of ambient N2O isotopomers by QCLAS, Atmos. Meas. Tech., 3, 609–618, 2010. |
|
|
|
|
|
|