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Measurement of the 13 C/ 12 C ratio of soil‐plant individual sugars by gas chromatography/combustion/isotope‐ratio mass spectrometry of silylated derivatives
Author(s) -
Derrien Delphine,
Balesdent Jérôme,
Marol Christine,
Santaella Catherine
Publication year - 2003
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.1269
Subject(s) - chemistry , isotope ratio mass spectrometry , isotopes of carbon , carbon fibers , mass spectrometry , gas chromatography , isotope , derivatization , combustion , gas chromatography–mass spectrometry , analytical chemistry (journal) , chromatography , environmental chemistry , organic chemistry , total organic carbon , materials science , physics , quantum mechanics , composite number , composite material
Carbohydrate is an important pool in the terrestrial carbon cycle. The potential offered by natural and artificial 13 C‐labelling techniques should therefore be applied to the investigation of the dynamics of individual sugars in soils. For this reason, we evaluated the method of 13 C sugar analysis by gas chromatography/combustion/isotope‐ratio mass spectrometry (GC/C/IRMS) after hydrolysis and direct trimethylsilylation. Trimethylsilylation involved the addition of several carbon atoms per sugar. These atoms have to be taken into account in the estimation of the carbon isotope ratio. The analysis of standard and natural pentoses and hexoses of known 13 C enrichments revealed that the number of analysed added carbon atoms was less than expected from stoichiometry. This was attributed to incomplete derivatization and/or incomplete oxidation of methylsilyl carbon before IRMS. Using a calibration of the number of analysed added carbon atoms, the isotope excess of enriched samples could be determined with a relative error close to 5%. Concerning the determination of natural abundances by GC/C/IRMS, we could measure the delta 13 C of standard C3‐ and C4‐derived sugars with an accuracy of ±1.5‰ using the previous calibration. We were able to apply this technique to plant‐soil systems labelled by pulse‐chase of 13 CO 2 , revealing the nature and dynamics of sugars in the plant rhizosphere. Copyright © 2003 John Wiley & Sons, Ltd.