 |
| Titel |
Automated CO2 extraction from air for clumped isotope analysis in the atmo- and biosphere |
| VerfasserIn |
Magdalena Hofmann, Martin Ziegler, Thijs Pons, Lucas Lourens, Thomas Röckmann |
| Konferenz |
EGU General Assembly 2015
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250111301
|
| Publikation (Nr.) |
 EGU/EGU2015-11406.pdf |
|
|
|
|
|
| Zusammenfassung |
| The conventional stable isotope ratios 13C/12C and 18O/16O in atmospheric CO2 are a
powerful tool for unraveling the global carbon cycle. In recent years, it has been suggested
that the abundance of the very rare isotopologue 13C18O16O on m/z 47 might be a promising
tracer to complement conventional stable isotope analysis of atmospheric CO2 [Affek and
Eiler, 2006; Affek et al. 2007; Eiler and Schauble, 2004; Yeung et al., 2009]. Here we present
an automated analytical system that is designed for clumped isotope analysis of atmo- and
biospheric CO2.
The carbon dioxide gas is quantitatively extracted from about 1.5L of air (ATP). The
automated stainless steel extraction and purification line consists of three main components:
(i) a drying unit (a magnesium perchlorate unit and a cryogenic water trap), (ii)
two CO2 traps cooled with liquid nitrogen [Werner et al., 2001] and (iii) a GC
column packed with Porapak Q that can be cooled with liquid nitrogen to -30ºC
during purification and heated up to 230ºC in-between two extraction runs. After
CO2 extraction and purification, the CO2 is automatically transferred to the mass
spectrometer. Mass spectrometric analysis of the 13C18O16O abundance is carried
out in dual inlet mode on a MATÂ253 mass spectrometer. Each analysis generally
consists of 80 change-over-cycles. Three additional Faraday cups were added to the
mass spectrometer for simultaneous analysis of the mass-to-charge ratios 44, 45,
46, 47, 48 and 49. The reproducibility for δ13C, δ18O and δ47 for repeated CO2
extractions from air is in the range of 0.11oÂ(SD), 0.18oÂ(SD) and 0.02 (SD)o
respectively.
This automated CO2 extraction and purification system will be used to analyse the
clumped isotopic signature in atmospheric CO2 (tall tower, Cabauw, Netherlands) and to
study the clumped isotopic fractionation during photosynthesis (leaf chamber experiments)
and soil respiration.
References
Affek, H. P., Xu, X. & Eiler, J. M., Geochim. Cosmochim. Acta 71, 5033–5043
(2007).
Affek, H. P. & Eiler, J. M., Geochim. Cosmochim. Acta 70, 1–12 (2006).
Eiler, J. M. & Schauble, E., Geochim. Cosmochim. Acta 68, 4767–4777 (2004).
Werner, R.A., Rothe, M. & Brand, W.A., Rapid Comm. Mass Spec. 15(22), 2152-2167
(2001)
Yeung, L. Y. et al., Proc. Natl. Acad. Sci. 106, 11496–11501 (2009). |
|
|
|
|
|
|