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A gas chromatographic/mass spectrometric method for tracing the microbial conversion of glucose into amino sugars in soil
Author(s) -
He Hongbo,
Xie Hongtu,
Zhang Xudong,
Wang Yanhong,
Wu Yeye
Publication year - 2005
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.2014
Subject(s) - chemistry , muramic acid , chromatography , galactosamine , amino acid , mass spectrometry , gas chromatography , electron ionization , chemical ionization , ion , glucosamine , organic chemistry , biochemistry , ionization , enzyme , peptidoglycan
Amino sugars in soils are heterogeneous and have been used as microbial residue biomarkers to investigate the microbial contribution to soil organic matter. However, it is not clear what the available carbon source is and how glucose is utilized for the synthesis of soil amino sugars. This paper presents a new gas chromatography/mass spectrometry (GC/MS) approach for the identification of 13 C incorporation into three amino sugars, D ‐glucosamine, D ‐galactosamine, and muramic acid, in soil incubated with U‐ 13 C‐glucose. Method evaluation showed that the chemical ionization (CI) mode was suitable for all these amino sugars, but that electron impact (EI) mode was applicable only to glucosamine and galactosamine. The 13 C conversion rate was estimated based on the abundance ratio of the ions corresponding to the masses of the ions F + n and F (where n is the skeleton carbon number in the fragment ions F of the amino sugars) and calculated as atom percentage excess. The reproducibility of the method was excellent and clearly adequate for the present purpose. In addition, the new approach is highly accurate as tested with mixtures of U‐ 13 C‐glucose and natural glucose. Copyright © 2005 John Wiley & Sons, Ltd.