Characterization of organic matter in particle size and density fractions from a red-brown earth by solid state 13C NMR

Soil Research ◽  
1987 ◽  
Vol 25 (1) ◽  
pp. 71 ◽  
Author(s):  
JM Oades ◽  
AM Vassallo ◽  
AG Waters ◽  
MA Wilson
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Particle Size ◽  
Organic Matter ◽  
Solid State ◽  
High Resolution ◽  
Iron Oxides ◽  
Density Fractions ◽  
13C Nuclear Magnetic Resonance ◽  
Solid State 13C Nmr

Size and density fractions separated from a red-brown earth have been analysed by high-resolution solidstate 13C nuclear magnetic resonance (n.m.r.) spectroscopy. Resonances from O-alkyl carbon (mainly carbohydrate) predominated in the spectra of the largest (250-2000 �m) fractions, whereas alkyl carbon resonances (mainly polymethylene) predominated in the spectra of clay fractions. Paramagnetics, mainly Fe3+, were found to influence the amount and type of carbon seen in 13C solid-state n.m.r. spectra of clay fractions containing more than several per cent iron oxides. Removal of iron oxides by reduction with dithionite allowed aromatics, carboxyls and carbohydrates to be detected by 13C n.m.r.

Quantitative Characterization of Soil Organic Matter and Its Fractionation Products by Solid State High Resolution C-13 (CPMAS) Spectroscopy

1991 ◽  
Vol 46 (11-12) ◽  
pp. 982-988 ◽  
Author(s):  
R. Fründ ◽  
H.-D. Lüdemann
Keyword(s):  
Organic Matter ◽  
Humic Acid ◽  
Solid State ◽  
Soil Organic Matter ◽  
High Resolution ◽  
Extraction Procedure ◽  
Chemical Information ◽  
Organic Carbon Content ◽  
Quantitative Characterization

Abstract In a systematic study the organic carbon content of typical Germ an soils was studied by solid state C-13 CPM AS spectroscopy.In order to check the quantitative validity of the standard sodium hydroxide extraction procedure, which fractionates soil organic matter into hum in, humic acid, and fulvic acid also the high resolution solid state spectra of these fractions were determined.The chemical information obtained from these spectra is discussed.

Comparison of nuclear magnetic resonance methods for the analysis of organic matter composition from soil density and particle fractions

2012 ◽  
Vol 9 (1) ◽  
pp. 97 ◽  
Author(s):  
Joyce S. Clemente ◽  
Edward G. Gregorich ◽  
André J. Simpson ◽  
Rajeev Kumar ◽  
Denis Courtier-Murias ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Solid State ◽  
Magnetic Resonance ◽  
1H Nmr ◽  
Solution State ◽  
Soil Fractions ◽  
13C Nuclear Magnetic Resonance ◽  
Nmr Methods ◽  
Solid State 13C Nmr ◽  
Nuclear Magnetic

Environmental contextThe association of specific organic matter (OM) compounds with clay mineral surfaces is believed to protect these compounds from degradation and thus result in long-term protection in soil. The molecular-level composition of soil OM associated with soil fractions was measured and compared using solid-state 13C nuclear magnetic resonance (NMR) and solution-state 1H NMR methods. Combining these methods allowed more detailed characterisation of OM associated with different soil fractions and will improve the understanding of OM dynamics in soil. AbstractOrganic matter (OM) associated with fine soil fractions is hypothesised to be protected from complete biodegradation by soil microbes. It is therefore important to understand the structure and stage of decomposition of OM associated with various soil fractions. Solid-state 13C nuclear magnetic resonance (NMR) spectroscopy has been used extensively to investigate the OM composition of soils and soil fractions. Solution-state 1H NMR spectroscopy has not been used as much but is an emerging tool for analysing soil OM because 1H NMR spectra are often better resolved and provide information that complements the structural information obtained from solid-state 13C NMR experiments. This study compares one-dimensional solution-state 1H NMR and solid-state 13C NMR methods for assessing the degradation and composition of OM in three different soils, and their light and clay-size fractions. The alkyl/O-alkyl degradation parameter was consistent across all NMR methods and showed that OM associated with clay-size fractions were at more advanced stages of degradation as compared to that in light density soil fractions. Solution-state 1H and diffusion edited (DE) 1H NMR results showed the presence of high concentrations of microbial-derived peptidoglycan and peptide side-chains in clay-sized fractions. Lignin was also identified in clay-sized fractions using solid-state 13C and solution-state 1H NMR techniques. The combination of solid-state 13C and solution-state 1H NMR methods provides a more detailed analysis of OM composition and thereby facilitates a better understanding of the fate and preservation of OM in soil.

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