Use of thermal analysis and solid-state 13C CP-MAS NMR spectroscopy to diagnose organic matter quality in relation to burn severity in Atlantic soils

Geoderma ◽  
2014 ◽  
Vol 226-227 ◽  
pp. 376-386 ◽  
Author(s):  
Agustín Merino ◽  
Andrea Ferreiro ◽  
Josefa Salgado ◽  
María T. Fontúrbel ◽  
Nieves Barros ◽  
...  
Keyword(s):  
Thermal Analysis ◽  
Organic Matter ◽  
Solid State ◽  
Nmr Spectroscopy ◽  
Mas Nmr ◽  
Burn Severity ◽  
Organic Matter Quality ◽  
Cp Mas Nmr ◽  
13C Cp Mas Nmr

Conformational characterization of poly(l-phenylalanine) in the solid state by 13C CP-MAS NMR spectroscopy

1988 ◽  
Vol 172 ◽  
pp. 395-400 ◽  
Author(s):  
Hidetoshi Miyamoto ◽  
Ryuji Takezaki ◽  
Tadashi Komoto ◽  
Isao Ando ◽  
Hazime Saitô ◽  
...  
Keyword(s):  
Solid State ◽  
Nmr Spectroscopy ◽  
Mas Nmr ◽  
Cp Mas Nmr ◽  
13C Cp Mas Nmr

Study of free and occluded particulate organic matter in soils by solid state 13C Cp/MAS NMR spectroscopy and scanning electron microscopy

Soil Research ◽  
1994 ◽  
Vol 32 (2) ◽  
pp. 285 ◽  
Author(s):  
A Golchin ◽  
JM Oades ◽  
JO Skjemstad ◽  
P Clarke
Keyword(s):  
Organic Matter ◽  
Solid State ◽  
Nmr Spectroscopy ◽  
Soil Carbon ◽  
Organic Materials ◽  
Dry Weight ◽  
Light Fraction ◽  
Carbon And Nitrogen ◽  
Cp Mas Nmr ◽  
13C Cp Mas Nmr

A simple densimetric method for the separation of free and occluded particulate organic materials was developed and applied to five virgin soils. The free organic matter was isolated by suspending the soil in sodium polytungstate solution (d = 1.6 Mg m-3) and decanting the light material. The remaining soil was disaggregated by sonification for liberation of occluded organic materials. The free light fraction consisted of large, undecomposed or partly decomposed root and plant fragments. This fraction comprised 0.59-4.34% of soil dry weight and accounted for 6.9-31.3% and 5.9-22.1% of total soil carbon and nitrogen respectively. Identifiable components of the occluded fraction were small particles of incompletely decomposed organic residues, pollen grains, particles of plant tissue such as lignin coils and phytoliths. This fraction comprised 0.69-1.81% of soil dry weight and represented 9.2-17.5% and 6.2-14.1% of the total soil carbon and nitrogen. The proportion of soil organic carbon recovered as the occluded fraction was high in soils with high clay contents. The chemical composition of occluded and free organic materials was investigated by solid-state 13C CP/MAS NMR spectroscopy. Despite the differences in soils, environmental conditions and vegetation, the organic structure of the free light fraction was similar in four of the five soils. This fraction consisted of 55-63% O-alkyl C, 18-25% alkyl C, 14-18% aromatic C, and 5-7% carbonyl C. In the other soil, this fraction showed a higher proportion of alkyl C (31%) and lower O-alkyl C (46%). Most of the differences between soils were associated with organic materials contained in the occluded light fraction. The differences in chemical structure between the occluded light fraction and free light fractions were similar in all examined soils. The NMR data showed that the proportion of O-alkyl C was lower and alkyl C higher in the occluded light fractions than in the free light fractions. The proportion of aromatic and carbonyl carbon was higher in the occluded fractions of three soils while the percentage of these two types of carbon remained unchanged in the two other soils. It is considered that the occluded organic matter is an old pool of carbon that has been accreted within aggregates during decades of root growth and it is that pool which is lost due to cultivation.

Early coalification features as approached by solid state 13C CP/MAS NMR spectroscopy

2006 ◽  
Vol 70 (4) ◽  
pp. 947-959 ◽  
Author(s):  
S. Kalaitzidis ◽  
A. Georgakopoulos ◽  
K. Christanis ◽  
A. Iordanidis
Keyword(s):  
Solid State ◽  
Nmr Spectroscopy ◽  
Mas Nmr ◽  
Cp Mas Nmr ◽  
13C Cp Mas Nmr
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