 |
| Titel |
Progress in the analysis and interpretation of N2O isotopes: Potential and future challenges |
| VerfasserIn |
Joachim Mohn, Béla Tuzson, Christoph Zellweger, Eliza Harris, Erkan Ibraim, Longfei Yu, Lukas Emmenegger |
| Konferenz |
EGU General Assembly 2017
|
| Medientyp |
Artikel
|
| Sprache |
en
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250143326
|
| Publikation (Nr.) |
 EGU/EGU2017-7034.pdf |
|
|
|
|
|
| Zusammenfassung |
| In recent years, research on nitrous oxide (N2O) stable isotopes has significantly advanced,
addressing an increasing number of research questions in biogeochemical and atmospheric
sciences [1]. An important milestone was the development of quantum cascade laser based
spectroscopic devices [2], which are inherently specific for structural isomers (15N14N16O
vs. 14N15N16O) and capable to collect real-time data with high temporal resolution,
complementary to the well-established isotope-ratio mass-spectrometry (IRMS) method. In
combination with automated preconcentration, optical isotope ratio spectroscopy (OIRS) has
been applied to disentangle source processes in suburban, rural and pristine environments
[e.g. 3, 4].
Within the European Metrology Research Programme (EMRP) ENV52 project
“Metrology for high-impact greenhouse gases (HIGHGAS)”, the quality of N2O stable
isotope analysis by OIRS, the comparability between laboratories, and the traceability to the
international isotope ratio scales have been addressed. An inter-laboratory comparison
between eleven IRMS and OIRS laboratories, organised within HIGHGAS, indicated limited
comparability for 15N site preference, i.e. the difference between 15N abundance in central
(N*NO) and end (*NNO) position [5]. In addition, the accuracy of the NH4NO3
decomposition reaction, which provides the link between 15N site preference and the
international 15N/14N scale, was found to be limited by non-quantitative NH4NO3
decomposition in combination with substantially different isotope enrichment factors for both
nitrogen atoms [6].
Results of the HIGHGAS project indicate that the following research tasks have to be
completed to foster research on N2O isotopes: 1) develop improved techniques to link the
15N and 18O abundance and the 15N site preference in N2O to the international stable
isotope ratio scales; 2) provide N2O reference materials, pure and diluted in an air
matrix, to improve inter-laboratory compatibility. These tasks will be addressed in the
upcoming European Metrology Programme for Innovation and Research (EMPIR)
project “Metrology for Stable Isotope Reference Standards (SIRS)” starting in June
2017.
Acknowledgement
Part of this work has been carried out within the European Metrology Research
Programme (EMRP) ENV52 project-HIGHGAS. The EMRP is jointly funded by the EMRP
participating countries within EURAMET and the European Union.
References
[1] S. Toyoda et al., Isotopocule analysis of biologically produced nitrous oxide in various
environments, Mass Spectrom. Rev., Doi 10.1002/mas.21459 (2015).
[2] J. Mohn et al., Site selective real-time measurements of atmospheric N2O isotopomers
by laser spectroscopy, Atmos. Meas. Tech. 5(7), 1601-1609 (2012).
[3] B. Wolf et al., First on-line isotopic characterization of N2O above intensively
managed grassland, Biogeosci. 12, 2517–2531, (2015).
[4] E. Harris et al., Tracking nitrous oxide emission processes at a suburban site with
semi-continuous, in-situ measurements of isotopic composition, J. Geophys. Res. Atmos.,
accepted (2016).
[5] J. Mohn et al., Interlaboratory assessment of nitrous oxide isotopomer analysis by
isotope ratio mass spectrometry and laser spectroscopy: current status and perspectives,
Rapid Commun. Mass Spectrom. 28, 1995–2007 (2014).
[6] J. Mohn et al. Reassessment of the NH4NO3 thermal decomposition technique for
calibration of the N2O isotopic composition, Rapid Commun. Mass Spectrom. 30,
2487–2496 (2016). |
|
|
|
|
|
|