Analysis of soil organic matter at the solid–water interface by nuclear magnetic resonance spectroscopy

2014 ◽  
Vol 11 (4) ◽  
pp. 472 ◽  
Author(s):  
Stephanie C. Genest ◽  
Myrna J. Simpson ◽  
André J. Simpson ◽  
Ronald Soong ◽  
David J. McNally
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Organic Matter ◽  
Humic Acid ◽  
Solid State ◽  
Nmr Spectroscopy ◽  
Magnetic Resonance ◽  
Soil Water ◽  
Mas Nmr ◽  
Water Interface ◽  
Preferential Sorption

Environmental context Structural and conformational information on organic matter–clay complexes and whole soils was obtained using different NMR methods. The results show that organic matter interactions with clay mineral surfaces determine the accessibility of specific organic matter components at the soil–water interface. This physical conformation may also play a role in soil biogeochemical processes and binding to pollutants in terrestrial environments. Abstract Organic matter (OM)–mineral interactions play an important role in OM preservation, global carbon cycling and contaminant transport. Studies have indicated that preferential sorption of OM is dependent on mineral type and solution conditions. In this study, 1H high resolution–magic angle spinning nuclear magnetic resonance (HR-MAS NMR) spectroscopy was employed to examine OM chemistry in organo-clay complexes. Dissolved OM from a forest soil, Leonardite humic acid and Peat humic acid were sorbed to Ca2+ enriched kaolinite and montmorillonite. As observed using 1H HR-MAS NMR spectroscopy, kaolinite sorbed mainly long-chain aliphatic compounds such as those from plant cuticles whereas montmorillonite sorbed a mixture of aliphatic components and proteins. These results show the preferential sorption of specific dissolved OM components on clay surfaces. This was tested further using solid-state 13C and 1H HR-MAS NMR analysis of whole soils containing kaolinite and montmorillonite as well as a Peat soil for contrast. The species present at the soil–water interface were mainly aliphatic components, carbohydrates and amino acids. Aromatic constituents were present in the soils (observed by solid-state 13C NMR and by 1H HR-MAS NMR spectroscopy when a more penetrating solvent was used) which signifies that these compounds likely exist in more hydrophobic domains that are buried and surface inaccessible. This study highlights the important role of OM interactions with clay minerals in the preservation of OM in soils and suggests that OM–OM associations may also play a role in the protection of specific OM components in soil.

scholarly journals Recent Advances in Solid-State Nuclear Magnetic Resonance Spectroscopy

2018 ◽  
Vol 11 (1) ◽  
pp. 485-508 ◽  
Author(s):  
Sharon E. Ashbrook ◽  
John M. Griffin ◽  
Karen E. Johnston
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Solid State ◽  
Nmr Spectroscopy ◽  
Magnetic Resonance ◽  
Solid State Nmr ◽  
Spectral Lines ◽  
Atomic Scale ◽  
Resonance Spectroscopy ◽  
Diverse Range ◽  
Nuclear Magnetic

The sensitivity of nuclear magnetic resonance (NMR) spectroscopy to the local atomic-scale environment offers great potential for the characterization of a diverse range of solid materials. Despite offering more information than its solution-state counterpart, solid-state NMR has not yet achieved a similar level of recognition, owing to the anisotropic interactions that broaden the spectral lines and hinder the extraction of structural information. Here, we describe the methods available to improve the resolution of solid-state NMR spectra and the continuing research in this area. We also highlight areas of exciting new and future development, including recent interest in combining experiment with theoretical calculations, the rise of a range of polarization transfer techniques that provide significant sensitivity enhancements, and the progress of in situ measurements. We demonstrate the detailed information available when studying dynamic and disordered solids and discuss the future applications of solid-state NMR spectroscopy across the chemical sciences.

Characterization of Natural Organic Matter by Nuclear Magnetic Resonance Spectroscopy

1997 ◽  
Author(s):  
Jerry A. Leenheer
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Organic Matter ◽  
Nmr Spectroscopy ◽  
Magnetic Resonance ◽  
Natural Organic Matter ◽  
Major Elements ◽  
Structure Information ◽  
Abundant Element ◽  
Nuclear Magnetic

Natural organic matter (NOM) is a major intermediate in the global carbon, nitrogen, sulfur, and phosphorus cycles. NOM is also the environmental matrix that frequently controls binding, transport, degradation, and toxicity of many organic and inorganic contaminants. Despite its importance, NOM is poorly understood at the structural chemistry level because of its molecular complexity and heterogeniety. Nuclear magnetic resonance (NMR) spectroscopy is one of the most useful spectrometric methods used to investigate NOM structure because qualitative and quantitative organic structure information for certain organic elements can be generated by NMR for NOM in both the solution and solid states under nondegradative conditions. However, NMR spectroscopy is not as sensitive as infrared or ultraviolet-visible spectroscopy; it is not at present applicable to organic oxygen and sulfur, and quantification of NMR spectra is difficult under certain conditions. The purpose of this overview is to present briefly the “state of the art” of NMR characterization of NOM, and to suggest future directions for NMR research into NOM. More comprehensive texts concerning the practice of NMR spectroscopy and its application to NOM in various environments have been produced by Wilson and by Wershaw and Mikita. Carbon, hydrogen, and oxygen are the major elements of NOM; together they comprise about 90% of the mass. The minor elements that constitute the remainder are nitrogen, sulfur, phosphorus, and trace amounts of the various halogen elements. With the exception of coal, in which carbon is the most abundant element, the order of relative abundance in NOM on an atomic basis is H > C > O > N > S > P = halogens. The optimum NMR-active nuclei for these elements are 1H, 13C, 17O, 15N, 33S, 31P, and 19F. The natural abundances and receptivities of these nuclei relative to 1H are given in Table 12.1. Quadrupolar effects for 17O, 33S, and halogen elements other than 19F lead to line broadening that greatly limits resolution in NMR studies of these elements in NOM.

Structure of poorly-ordered aluminosilicates

Clay Minerals ◽  
1986 ◽  
Vol 21 (5) ◽  
pp. 879-897 ◽  
Author(s):  
M. A. Wilson ◽  
S. A. McCarthy ◽  
P. M. Fredericks
Keyword(s):  
Electron Microscopy ◽  
Nuclear Magnetic Resonance ◽  
Fourier Transform ◽  
Solid State ◽  
Nmr Spectroscopy ◽  
Magnetic Resonance ◽  
High Resolution ◽  
Ftir Spectroscopy ◽  
Driving Forces ◽  
Repulsive Forces

AbstractThe structure of synthetic aluminosilicates prepared at pH 6 has been investigated by 29Si and 27Al high-resolution solid-state nuclear magnetic resonance (NMR) spectroscopy. Fourier transform infrared (FTIR) spectroscopy and electron microscopy have also been used to characterize the products. The amount of Si and Al in protoimogolite, disordered allophane and other structures has been measured. There is a fair correlation between the intensity of the 349 cm−1 band in the FTIR spectra and the proportion by weight of protoimogolite Si measured by NMR. It is shown that disordered allophanes have similar structures to those proposed by van Reeuwijk and de Villiers (Soil Sci. Soc. Am. Proc. 32 (1968) 238–240), i.e. octahedral Al surrounding a tetrahedral core. Moreover, it is clear that at high Al:Si ratios (⩾1:1), protoimogolite can compete with disordered allophane precursors for aluminum. The driving forces for formation of protoimogolite rather than allophane appear to be long range Al-Al repulsive forces through oxygen.

Structural Characterization of Ca2+-ATPase-Bound Phospholamban in Lipid Bilayers by Solid-State Nuclear Magnetic Resonance (NMR) Spectroscopy†,‡

Biochemistry ◽  
2008 ◽  
Vol 47 (15) ◽  
pp. 4369-4376 ◽  
Author(s):  
Karsten Seidel ◽  
Ovidiu C. Andronesi ◽  
Joachim Krebs ◽  
Christian Griesinger ◽  
Howard S. Young ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Solid State ◽  
Nmr Spectroscopy ◽  
Magnetic Resonance ◽  
Lipid Bilayers ◽  
Structural Characterization ◽  
Nuclear Magnetic

An NMR Study of Hydrogen in Si02 Films on Silicon

1989 ◽  
Vol 159 ◽  
Author(s):  
David H. Levy ◽  
K. K. Gleason
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Solid State ◽  
Nmr Spectroscopy ◽  
Magnetic Resonance ◽  
Half Width ◽  
Silicon Substrates ◽  
Half Maximum ◽  
Lorentzian Line ◽  
Nmr Study ◽  
Dry Film

ABSTRACTWe have used solid state nuclear magnetic resonance (NMR) spectroscopy to study both “wet” and “dry” thermally grown films of SiO2 on silicon substrates. For the 5000 § wet film, grown at 1050 °C we observed a single Lorentzian line of 6 kHz HWHM (half width at half maximum). For the 500 § dry film, we observed a convolution of two lines: a) a Lorentzian of 4 kHz HWHM and b) a Gaussian of 20 kHz HWHM. The hydrogen distributions in both oxides are interpreted as a function of these lines.

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