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3. | | SONG, G.; NOVOTNY, E. H.; HAYES, M. H. B.; AZEVEDO, E. R. de; BONAGAMBA, T. J. Char and humin fractions in Amazonian dark earths. In: INTERNATIONAL MEETING OF THE INTERNATIONAL HUMIC SUBSTANCES SOCIETY, 14., 2008, Saint Petersburg. From molecular understanding to innovative applications of humic substances: proceedings... Moscow: Lomonosov Moscow State University, 2008. v. 1, p. 311-314. Biblioteca(s): Embrapa Solos. |
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| Acesso ao texto completo restrito à biblioteca da Embrapa Instrumentação. Para informações adicionais entre em contato com cnpdia.biblioteca@embrapa.br. |
Registro Completo
Biblioteca(s): |
Embrapa Instrumentação. |
Data corrente: |
30/03/2021 |
Data da última atualização: |
09/06/2022 |
Tipo da produção científica: |
Artigo em Periódico Indexado |
Circulação/Nível: |
A - 1 |
Autoria: |
FACCHINATTO, W. M.; GARCIA, R. H. S.; SANTOS, D. M.; FIAMINGO, A.; FLORES, D. W. M.; CAMPANA-FILHO, S. P.; AZEVEDO, E. R.; COLNAGO, L. A. |
Afiliação: |
LUIZ ALBERTO COLNAGO, CNPDIA. |
Título: |
Fast-forward approach of time-domain NMR relaxometry for solid-state chemistry of chitosan. |
Ano de publicação: |
2021 |
Fonte/Imprenta: |
Carbohydrate Polymers, v. 256, 117576, 2021. |
Páginas: |
1 - 10 |
ISSN: |
0144-8617 |
DOI: |
https://doi.org/10.1016/j.carbpol.2020.117576 |
Idioma: |
Inglês |
Conteúdo: |
Chitosans with different average degrees of acetylation and weight molecular weight were analyzed by timedomain NMR relaxometry using the recently proposed pulse sequence named Rhim and Kessemeier - Radiofrequency Optimized Solid-Echo (RK-ROSE) to acquire 1 H NMR signal of solid-state materials. The NMR signal decay was composed of faster (tenths of μs) and longer components, where the mobile-part fraction exhibited an effective relaxation transverse time assigned to methyl hydrogens from N-acetyl-D-glucosamine (GlcNAc) units. The higher intrinsic mobility of methyl groups was confirmed via DIPSHIFT experiments by probing the 1 H-13C dipolar interaction. RK-ROSE data were modeled by using Partial Least Square (PLS) multivariate regression, which showed a high coefficient of determination (R2 > 0.93) between RK-ROSE signal profile and average degrees of acetylation and crystallinity index, thus indicating that time-domain NMR consists in a promising tool for structural and morphological characterization of chitosan. |
Palavras-Chave: |
Crystallinity; Degree of acetylation; Relaxometry; TD-NMR. |
Categoria do assunto: |
-- |
Marc: |
LEADER 01879naa a2200289 a 4500 001 2130986 005 2022-06-09 008 2021 bl uuuu u00u1 u #d 022 $a0144-8617 024 7 $ahttps://doi.org/10.1016/j.carbpol.2020.117576$2DOI 100 1 $aFACCHINATTO, W. M. 245 $aFast-forward approach of time-domain NMR relaxometry for solid-state chemistry of chitosan.$h[electronic resource] 260 $c2021 300 $a1 - 10 520 $aChitosans with different average degrees of acetylation and weight molecular weight were analyzed by timedomain NMR relaxometry using the recently proposed pulse sequence named Rhim and Kessemeier - Radiofrequency Optimized Solid-Echo (RK-ROSE) to acquire 1 H NMR signal of solid-state materials. The NMR signal decay was composed of faster (tenths of μs) and longer components, where the mobile-part fraction exhibited an effective relaxation transverse time assigned to methyl hydrogens from N-acetyl-D-glucosamine (GlcNAc) units. The higher intrinsic mobility of methyl groups was confirmed via DIPSHIFT experiments by probing the 1 H-13C dipolar interaction. RK-ROSE data were modeled by using Partial Least Square (PLS) multivariate regression, which showed a high coefficient of determination (R2 > 0.93) between RK-ROSE signal profile and average degrees of acetylation and crystallinity index, thus indicating that time-domain NMR consists in a promising tool for structural and morphological characterization of chitosan. 653 $aCrystallinity 653 $aDegree of acetylation 653 $aRelaxometry 653 $aTD-NMR 700 1 $aGARCIA, R. H. S. 700 1 $aSANTOS, D. M. 700 1 $aFIAMINGO, A. 700 1 $aFLORES, D. W. M. 700 1 $aCAMPANA-FILHO, S. P. 700 1 $aAZEVEDO, E. R. 700 1 $aCOLNAGO, L. A. 773 $tCarbohydrate Polymers$gv. 256, 117576, 2021.
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