Measurement of δ13C values of soil amino acids by GC-C-IRMS using trimethylsilylation: a critical assessment.
Isotopes Environ Health Stud
; 50(4): 516-30, 2014.
Article
em En
| MEDLINE
| ID: mdl-25331967
ABSTRACT
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 δ(13)C 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 δ(13)C for di-, tri- and tetra-TMS derivatives. For soil samples, only four amino acids (leucine, valine, threonine and serine) provide reliable δ(13)C values with a total average uncertainty of 1.3â
. We conclude that trimethylsilyl derivatives are only suitable for determining the (13)C incorporation in amino acids within experiments using (13)C-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.
Palavras-chave
Texto completo:
1
Temas:
ECOS
/
Aspectos_gerais
Bases de dados:
MEDLINE
Assunto principal:
Plantas
/
Isótopos de Carbono
/
Monitoramento Ambiental
/
Aminoácidos
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Cromatografia Gasosa-Espectrometria de Massas
Tipo de estudo:
Diagnostic_studies
Idioma:
En
Revista:
Isotopes Environ Health Stud
Assunto da revista:
SAUDE AMBIENTAL
Ano de publicação:
2014
Tipo de documento:
Article
País de afiliação:
Itália