Universität zu Köln

Sun, Shuwen, Meyer, Vera D., Dolman, Andrew M., Winterfeld, Maria, Hefter, Jens ORCID: 0000-0002-5823-1966, Dummann, Wolf ORCID: 0000-0001-6054-2440, McIntyre, Cameron, Montlucon, Daniel B., Haghipour, Negar, Wacker, Lukas, Gentz, Torben, van der Voort, Tessa S., Eglinton, Timothy, I and Mollenhauer, Gesine ORCID: 0000-0001-5138-564X (2020). C-14 BLANK ASSESSMENT IN SMALL-SCALE COMPOUND-SPECIFIC RADIOCARBON ANALYSIS OF LIPID BIOMARKERS AND LIGNIN PHENOLS. Radiocarbon, 62 (1). S. 207 - 219. TUCSON: UNIV ARIZONA DEPT GEOSCIENCES. ISSN 1945-5755

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Abstract

Compound-specific radiocarbon (C-14) dating often requires working with small samples of < 100 mu g carbon (mu gC). This makes the radiocarbon dates of biomarker compounds very sensitive to biases caused by extraneous carbon of unknown composition, a procedural blank, which is introduced to the samples during the steps necessary to prepare a sample for radiocarbon analysis by accelerator mass spectrometry (i.e., isolating single compounds from a heterogeneous mixture, combustion, gas purification and graphitization). Reporting accurate radiocarbon dates thus requires a correction for the procedural blank. We present our approach to assess the fraction modern carbon ((FC)-C-14) and the mass of the procedural blanks introduced during the preparation procedures of lipid biomarkers (i.e. n-alkanoic acids) and lignin phenols. We isolated differently sized aliquots (6-151 mu gC) of n-alkanoic acids and lignin phenols obtained from standard materials with known (FC)-C-14 values. Each compound class was extracted from two standard materials (one fossil, one modern) and purified using the same procedures as for natural samples of unknown (FC)-C-14. There is an inverse linear relationship between the measured (FC)-C-14 values of the processed aliquots and their mass, which suggests constant contamination during processing of individual samples. We use Bayesian methods to fit linear regression lines between (FC)-C-14 and 1/mass for the fossil and modern standards. The intersection points of these lines are used to infer (FCblank)-C-14 and m(blank) and their associated uncertainties. We estimate 4.88 +/- 0.69 mu gC of procedural blank with (FC)-C-14 of 0.714 +/- 0.077 for n-alkanoic acids, and 0.90 +/- 0.23 mu gC of procedural blank with (FC)-C-14 of 0.813 +/- 0.155 for lignin phenols. These (FCblank)-C-14 and m(blank)( )can be used to correct AMS results of lipid and lignin samples by isotopic mass balance. This method may serve as a standardized procedure for blank assessment in small-scale radiocarbon analysis.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Sun, Shuwen UNSPECIFIED UNSPECIFIED UNSPECIFIED Meyer, Vera D. UNSPECIFIED UNSPECIFIED UNSPECIFIED Dolman, Andrew M. UNSPECIFIED UNSPECIFIED UNSPECIFIED Winterfeld, Maria UNSPECIFIED UNSPECIFIED UNSPECIFIED Hefter, Jens UNSPECIFIED orcid.org/0000-0002-5823-1966 UNSPECIFIED Dummann, Wolf UNSPECIFIED orcid.org/0000-0001-6054-2440 UNSPECIFIED McIntyre, Cameron UNSPECIFIED UNSPECIFIED UNSPECIFIED Montlucon, Daniel B. UNSPECIFIED UNSPECIFIED UNSPECIFIED Haghipour, Negar UNSPECIFIED UNSPECIFIED UNSPECIFIED Wacker, Lukas UNSPECIFIED UNSPECIFIED UNSPECIFIED Gentz, Torben UNSPECIFIED UNSPECIFIED UNSPECIFIED van der Voort, Tessa S. UNSPECIFIED UNSPECIFIED UNSPECIFIED Eglinton, Timothy, I UNSPECIFIED UNSPECIFIED UNSPECIFIED Mollenhauer, Gesine UNSPECIFIED orcid.org/0000-0001-5138-564X UNSPECIFIED
URN:	urn:nbn:de:hbz:38-347631
DOI:	10.1017/RDC.2019.108
Journal or Publication Title:	Radiocarbon
Volume:	62
Number:	1
Page Range:	S. 207 - 219
Date:	2020
Publisher:	UNIV ARIZONA DEPT GEOSCIENCES
Place of Publication:	TUCSON
ISSN:	1945-5755
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language CARBON; AMS Multiple languages Geochemistry & Geophysics Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/34763