Universität zu Köln

Wotte, Anja ORCID: 0000-0002-1875-8376, Wischhoefer, Philipp, Wacker, Lukas and Rethemeyer, Janet (2017). (CO2)-C-14 analysis of soil gas: Evaluation of sample size limits and sampling devices. Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms, 413. S. 51 - 57. AMSTERDAM: ELSEVIER. ISSN 1872-9584

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Abstract

Radiocarbon (C-14) analysis of CO2 respired from soils or sediments is a valuable tool to identify different carbon sources. The collection and processing of the CO2, however, is challenging and prone to contamination. We thus continuously improve our handling procedures and present a refined method for the collection of even small amounts of CO2 in molecular sieve cartridges (MSCs) for accelerator mass spectrometry C-14 analysis. Using a modified vacuum rig and an improved desorption procedure, we were able to increase the CO2 recovery from the MSC (95%) as well as the sample throughput compared to our previous study. By processing series of different sample size, we show that our MSCs can be used for CO2 samples of as small as 50 mu g C. The contamination by exogenous carbon determined in these laboratory tests, was less than 2.0 mu g C from fossil and less than 3.0 mu g C from modern sources. Additionally, we tested two sampling devices for the collection of CO2 samples released from soils or sediments, including a respiration chamber and a depth sampler, which are connected to the MSC. We obtained a very promising, low process blank for the entire CO2 sampling and purification procedure of similar to 0.004 (FC)-C-14 (equal to 44,000 yrs BP) and similar to 0.003 (FC)-C-14 (equal to 47,000 yrs BP). In contrast to previous studies, we observed no isotopic fractionation towards lighter delta C-13 values during the passive sampling with the depth samplers.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Wotte, Anja UNSPECIFIED orcid.org/0000-0002-1875-8376 UNSPECIFIED Wischhoefer, Philipp UNSPECIFIED UNSPECIFIED UNSPECIFIED Wacker, Lukas UNSPECIFIED UNSPECIFIED UNSPECIFIED Rethemeyer, Janet UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-207850
DOI:	10.1016/j.nimb.2017.10.009
Journal or Publication Title:	Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms
Volume:	413
Page Range:	S. 51 - 57
Date:	2017
Publisher:	ELSEVIER
Place of Publication:	AMSTERDAM
ISSN:	1872-9584
Language:	English
Faculty:	Faculty of Mathematics and Natural Sciences
Divisions:	Faculty of Mathematics and Natural Sciences > Department of Geosciences > Institute of Geology and Mineralog
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language ZEOLITE MOLECULAR-SIEVE; CARBON-DIOXIDE; LAACHER SEE; RADIOCARBON ANALYSIS; PERMAFROST CARBON; ORGANIC-CARBON; RESPIRATION; C-14; CO2; CLIMATE Multiple languages Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/20785