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Characterization of alkyl carbon in forest soils by CPMAS 13C NMR spectroscopy and dipolar dephasing

Science of the Total Environment

By:
,
DOI: 10.1016/0048-9697(89)90122-8

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Abstract

Samples obtained from forest soils at different stages of decomposition were treated sequentially with chloroform/methanol (extraction of lipids), sulfuric acid (hydrolysis), and sodium chlorite (delignification) to enrich them in refractory alkyl carbon. As revealed by NMR spectroscopy, this treatment yielded residues with high contents of alkyl carbon. In the NMR spectra of residues obtained from litter samples, resonances for carbohydrates are also present, indicating that these carbohydrates are tightly bound to the alkyl carbon structures. During decomposition in the soils this resistant carbohydrate fraction is lost almost completely. In the litter samples the alkyl carbon shows a dipolar dephasing behavior indicative of two structural components, a rigid and a more mobile component. As depth and decomposition increase, only the rigid component is observed. This fact could be due to selective degradation of the mobile component or to changes in molecular mobility during decomposition, e.g., because of an increase in cross linking or contact with the mineral matter of the soil.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Characterization of alkyl carbon in forest soils by CPMAS 13C NMR spectroscopy and dipolar dephasing
Series title:
Science of the Total Environment
DOI:
10.1016/0048-9697(89)90122-8
Volume
81-82
Issue:
C
Year Published:
1989
Language:
English
Publisher:
Elsevier
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
First page:
169
Last page:
177
Number of Pages:
9