Search results for "CPMAS"

showing 3 items of 13 documents

Effect of Heating Time and Temperature on the Chemical Characteristics of Biochar from Poultry Manure

2014

Poultry manure (PM) chars were obtained at different temperatures and charring times. Chemical-physical characterization of the different PM chars was conducted by cross-polarization magic angle spinning (CPMAS) (13)C NMR spectroscopy and thermal analysis. CPMAS (13)C NMR spectra showed that the chemical composition of PM char is dependent on production temperature rather than on production duration. Aromatic and alkyl domains in the PM chars obtained at the lowest temperatures remained unchanged at all heating times applied for their production. The PM char obtained at the highest temperature consisted only of aromatic structures having chemical nature that also appeared invariant with hea…

chemistry.chemical_classificationHot TemperatureMagnetic Resonance SpectroscopyTime FactorsSettore AGR/13 - Chimica AgrariaAnalytical chemistryGeneral ChemistryPoultryManureThermogravimetrychar poultry manure CPMAS 13C NMR TGA DTG thermal stabilitychemistryCharcoalSpectroscopy Fourier Transform InfraredBiocharMagic angle spinningAnimalsOrganic chemistryCharringCharGeneral Agricultural and Biological SciencesThermal analysisChemical compositionAlkyl
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Interactions between 2-Aminobenzothiazole and Natural Organic Matter as Evidenced by CPMAS Nitrogen-15 NMR Spectroscopy

2009

Cross-polarization magic angle spinning (CPMAS) 15N nuclear magnetic resonance (NMR) spectroscopy was used to study the interactions between 2-aminobenzothiazole (ABT) and natural organic matter in the presence of the natural enzyme laccase and synthetic air. Through the use of synthesized model compounds, we were able to confirm previous findings by CPMAS 13C NMR spectroscopy that showed the formation of covalent amide bonds. We also provide evidence of the presence of two additional H bonds between ABT and the natural organic matter. Both H bonds involved the amino and thiazole groups of ABT.

chemistry.chemical_classificationHydrogen bondSettore AGR/13 - Chimica AgrariaHASoil Science2-aminobenzothiazolenuclear magnetic resonance.Nuclear magnetic resonance spectroscopyCPMAShumic acidCarbon-13 NMRABTNMRchemistry.chemical_compoundchemistryCovalent bondMagic angle spinningOrganic chemistryOrganic mattercross-polarization magic angle spinningHPLChigh-performance liquid chromatographyThiazoleSpectroscopy
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Effect of ramp size and sample spinning speed on CPMAS 13C NMR spectra of soil organic matter

2011

Abstract Cross polarization (CP) magic angle spinning (MAS) 13C NMR spectroscopy is a solid state NMR technique widely applied to study the chemical composition of natural organic matter. In high magnetic fields (>7 T), fast sample spinning is required in order to reduce the influence of spinning sidebands underlying other chemical shift regions. As the spinning speed increases, the Hartmann–Hahn matching profiles break down into a series of narrow matching bands. In order to account for this instability variable amplitude cross polarization techniques (e.g. VACP, ramp-CP) have been developed. In the present study, we experimentally verified the stability of the Hartmann–Hahn condition unde…

chemistry.chemical_classificationSettore AGR/13 - Chimica AgrariaAnalytical chemistryCarbon-13 NMRSpectral lineMagnetic fieldAmplitudeSolid-state nuclear magnetic resonancechemistryGeochemistry and Petrologysoil organic matterCPMAS 13C NMRMagic angle spinningHumic acidSpinningOrganic Geochemistry
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