Rubino, M, Milin, S, D'Onofrio, A, Signoret, P, Hatte, C and Balesdent, J (2014) Measurement of delta C-13 values of soil amino acids by GC-C-IRMS using trimethylsilylation: a critical assessment. Isotopes in Environmental and Health Studies, 50 (4). 516 - 530. ISSN 1025-6016

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In this study, we evaluated trimethylsilyl (TMS) derivatives as derivatization reagents for the compound-specific stable carbon isotope analysis of soil amino acids by gas chromatography–combustion–isotope ratio mass spectrometry (GC–C–IRMS). We used non-proteinogenic amino acids to show that the extraction–derivatization–analysis procedure provides a reliable method to measure δ13C values of amino acids extracted from soil. However, we found a number of drawbacks that significantly increase the final total uncertainty. These include the following: production of multiple peaks for each amino acid, identified as di-, tri- and tetra-TMS derivatives; a number of TMS-carbon (TMS-C) atoms added lower than the stoichiometric one, possibly due to incomplete combustion; different TMS-C δ13C for di-, tri- and tetra-TMS derivatives.

For soil samples, only four amino acids (leucine, valine, threonine and serine) provide reliable δ13C values with a total average uncertainty of 1.3 ‰. We conclude that trimethylsilyl derivatives are only suitable for determining the 13C incorporation in amino acids within experiments using 13C-labelled tracers but cannot be applied for amino acids with natural carbon isotope abundance until the drawbacks described here are overcome and the measured total uncertainty significantly decreased.

Item Type: Article
Additional Information: The final published version can be accessed online at - please refer to any terms and conditions of use of the publisher.
Uncontrolled Keywords: carbon-13, gas chromatography–combustion–isotope ratio mass spectrometry, isotope analysis, soil amino acids, trimethylsilylation
Subjects: G Geography. Anthropology. Recreation > GE Environmental Sciences
Divisions: Faculty of Natural Sciences > School of Geography, Geology and the Environment
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Depositing User: Symplectic
Date Deposited: 15 May 2018 09:14
Last Modified: 15 May 2018 10:34

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