Application of INEPT nitrogen-15 and silicon-29 nuclear magnetic resonance spectrometry to derivatized fulvic acids

Thorn, Kevin A.; Folan, Daniel W.; Arterburn, Jeffrey B.; Mikita, Michael A.; MacCarthy, Patrick

doi:10.1016/0048-9697(89)90127-7

Cited by 21 publications

(16 citation statements)

References 15 publications

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“…Humic acids were invariably adsorbed more strongly than fulvic acids. Although the characteristics of humic substances may vary widely depending on the source material, it is generally accepted that humic acids have greater phenolic content, greater aromaticity, greater carbon, greater molar volume (molecular weight), and less oxygen than the corresponding fulvic acids (43)(44)(45). Elemental ratios of oxygen and carbon have previously been used as an indication of the polarity of the humic substance (10,13).…”

Section: Resultsmentioning

confidence: 99%

Influence of mineral-bound humic substances on the sorption of hydrophobic organic compounds

Murphy¹,

Zachara²,

Smith³

1990

Environ. Sci. Technol.

428

307

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The sorption of three hydrophobic organic compounds (HOC) was investigated on hematite and kaolinite that had been coated with natural humic substances over a mass percent carbon range of 0.01-O.5%. Increasing quantities of sorbed humic substances increased the sorption of HOC. Anthracene, the most hydrophobic HOC, showed the greatest sorption enhancement, while the most aromatic coating, peat humic acid, was the strongest sorbent. Depending on the type of humic acid coating and the mineral substrate, the experimental K , values were either higher or lower than those predicted by the Kow The sorptivity of a given humic acid for HOC was not the same on kaolinite and hematite, suggesting that the orientation and structure of the humic substance on the mineral may affect the surface area of the organic phase and the accessibility of hydrophobic domains that control HOC sorptivity. Sorption isotherms for HOC on the humic-coated mineral substrates were nonlinear, implying that the sorption phenomenon was adsorption onto rather than partitioning into the surface organic phase.

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Section: Resultsmentioning

confidence: 99%

Influence of mineral-bound humic substances on the sorption of hydrophobic organic compounds

Murphy¹,

Zachara²,

Smith³

1990

Environ. Sci. Technol.

428

307

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“…In contrast to I3C-NMR, the application of solid-state 15N-NMR to N-containing geomacromolecules has been hampered by the fact that its sensitivity is approximately 50 times lower than that of 13C-NMR. Consequently, 15N-NMR is more successful when 15N-enriched material s are used , 1986Thorn et al, 1989;Cheshire et al, 1990;Almendros et al, 1991;Knicker and Lüdemann, 1995;Clinton et al, 1996;Potthast et al, 1996;González-Vila et al, 2001a). Preston et al (1986) was the first author to publish a solid-state 15N-NMR spectrum ofhumic material from a peat with natural 15N-abundance and N content ca.…”

Section: Analytical Approaches To Monitor Changes In the Molecular Comentioning

confidence: 99%

Thermal Transformation of Soil Organic Matter by Natural Fires and Laboratory-Controlled Heatings

González-Vila

Galmendros

2003

Natural and Laboratory-Simulated Thermal Geochemical Processes

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The results of a multi-approach analysis on the effects that wildfires exert on soil organic matter (SOM) properties are presented. The methods used included wet chemical oxidation and therrnal degradation by flash pyrolysis, as well as Fourier-transformed infrared (FT-IR) and solid-state l3C and 15N nuclear magnetic resonance (NMR) spectroscopies. Such destructive and non-destructive analytical techniques were used for the assessment of heat effects to a molecular level applied to representative Spanish forest ecosystems and for the study of the alteration of different organic materials in the course of progressive heating in laboratory simulation experiments. The material s studied included: whole soils and sapric peat, isolated soil humic fractions, lignocellulosic biomass and preparations of cellulose. Among our findings, it can be emphasized: (i) the importance of the abiotic transformation of aliphatic precursors into aromatic macromolecules under present-day environmental conditions, (ii) a therrnal neoforrnation of heterocyclic N-forms, (iii) changes in the solubility properties of the soluble and colloidal SOM fractions, (iv) a preferentialloss of oxygen-containing functional groups and O-alkyl aliphatic structures, and (v) changes in the SOM macromolecular structure, probably related to the accumulation of a resistant alkyl moiety. In general, our results from laboratory experiments agreed with those obtained from soils affected by wildfires in different Continental Mediterranean forest forrnations. The results are discussed in terrns of the natural stabilization mechanisms of the most refractory SOM forrns, which is of particular interest in the study of the global C and N biogeochemical cycles.

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“…28 In that case, the quaternary carbons do not benefit from the sensitivity gain, which has no interest for the present issue. Other studies used the polarization transfer via the long-range scalar coupling by adjusting the first delay in the INEPT scheme (Figure 1), that is 1/4J, to the n J CH values as done for 29 Si. 29 This is the approach we have chosen for getting the full spectrum in irm- 13 C INEPT (FS-INEPT).…”

mentioning

confidence: 99%

“…Other studies used the polarization transfer via the long-range scalar coupling by adjusting the first delay in the INEPT scheme (Figure 1), that is 1/4J, to the n J CH values as done for 29 Si. 29 This is the approach we have chosen for getting the full spectrum in irm- 13 C INEPT (FS-INEPT). The present work aimed to delineate the experimental conditions from the sample preparation to the NMR parameters to reach the double target: (i) sensitivity gain for the full 13 C spectrum, while (ii) keeping a high precision in the 13 C isotope profiles.…”

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confidence: 99%

Full Spectrum Isotopic ¹³C NMR Using Polarization Transfer for Position-Specific Isotope Analysis

et al. 2018

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For the last ten years, quantitative isotope ratio monitoring C NMR (irm-C NMR) has been successfully tested and proven as an efficient tool for the determination of position-specific C/C ratios. Several applications in different domains have shown the interest in this technique. In the context of origin assignment, the possibility to track the distribution network of illicit drugs or cutting agents is of prime importance. However irm-C NMR still suffers from a relative lack of sensitivity limiting its dissemination among control laboratories. Improvements were proposed to reduce experiment time by using the INEPT sequence ("Insensitive Nuclei Enhanced by Polarization Transfer") based on polarization transfer from highly sensitive H to less sensitiveC. Several applications based on the use of the one bond scalar coupling between H andC ( J) have shown the potential of this methodology in terms of short experimental duration. However, the isotopic information given by quaternary carbons was lost. The aim of this study is to extend this approach by using short- and long-range coupling ( J, J, and J) in order to have access to all C/C position-specific ratios, i.e., acquisition of the full spectrum (FS-INEPT). It is shown that this innovative tool provides both sensitivity gain-thanks to the long-range polarization transfer-and appropriate repeatability. The relative isotopic profiles allowed the classification of two cutting agents, caffeine and paracetamol (acetaminophen), according to their origin, as it was previously observed with "classical" irm-C NMR but consuming much less sample and/or reducing the experimental time.

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Application of INEPT nitrogen-15 and silicon-29 nuclear magnetic resonance spectrometry to derivatized fulvic acids

Cited by 21 publications

References 15 publications

Influence of mineral-bound humic substances on the sorption of hydrophobic organic compounds

Influence of mineral-bound humic substances on the sorption of hydrophobic organic compounds

Thermal Transformation of Soil Organic Matter by Natural Fires and Laboratory-Controlled Heatings

Full Spectrum Isotopic ¹³C NMR Using Polarization Transfer for Position-Specific Isotope Analysis

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Application of INEPT nitrogen-15 and silicon-29 nuclear magnetic resonance spectrometry to derivatized fulvic acids

Cited by 21 publications

References 15 publications

Influence of mineral-bound humic substances on the sorption of hydrophobic organic compounds

Influence of mineral-bound humic substances on the sorption of hydrophobic organic compounds

Thermal Transformation of Soil Organic Matter by Natural Fires and Laboratory-Controlled Heatings

Full Spectrum Isotopic 13C NMR Using Polarization Transfer for Position-Specific Isotope Analysis

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Product

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Full Spectrum Isotopic ¹³C NMR Using Polarization Transfer for Position-Specific Isotope Analysis