title: Effect of 13C enrichment and sugar type on analysis of sugars by gas chromatography/combustion/isotope ratio mass spectrometry.
abstract: BACKGROUND
  The objective of this investigation was to test gas-chromatographic compound-specific analysis for studies on the isotopic composition of (13)C-enriched sugar molecules. The effects of (13)C enrichment and type of sugar (C5, C6) will provide valuable information on isotopic correction for future studies employing (13)C-enriched sugars.
  
  
  METHODS
  Five sugar solutions of xylose, mannose and glucose with (13)C enrichments ranging between 1.1 and 1.5 atom-% were prepared. The (13)C enrichments of the initial sugars were measured by elemental analyser/isotope ratio mass spectrometry (EA/IRMS); (13)C enrichments for derivatised sugars were obtained by gas chromatography/combustion/IRMS (GC/C/IRMS).
  
  
  RESULTS
  The linear relationships between the (13)C enrichments of the initial sugars and the values for the derivatised sugars were sugar-type dependent. Corrections for GC/C/IRMS values took into account the kinetic isotope effect (KIE) of the derivatising agent associated with the coefficient (K(d)) and a newly introduced second coefficient (K(c)) associated with the KIE of the sugar. While K(d) was constant, K(c) varied with sugar type. During derivatisation acetate groups with (12)C and sugars with more (13)C reacted faster.
  
  
  CONCLUSIONS
  Coefficients for the specific ranges of (13)C enrichments under study have to be assessed and the reactions of different sugar types have to be taken into account to avoid underestimation of (13)C enrichment of up to 9% (C5) or overestimation of up to 4% (C6).
authors: Laboratoire de Biogéochimie et Ecologie des Milieux Continentaux, CNRS-INRA-AgroParisTech UPMC-UPEC-IRD, Thiverval-Grignon, France. karen.baumann@web.de
authors: Karen
authors: K
authors: Baumann
authors: Marie-France
authors: MF
authors: Dignac
authors: Gérard
authors: G
authors: Bardoux
authors: Cornelia
authors: C
authors: Rumpel
mesh_terms: D002247:Carbon Isotopes / Q000032:analysis* / Q000737:chemistry; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D016014:Linear Models; D009005:Monosaccharides / Q000032:analysis* / Q000737:chemistry
chemical_list: D002247:Carbon Isotopes; D009005:Monosaccharides