Fast-forward approach of time-domain NMR relaxometry for solid-state chemistry of chitosan.

Autor: Facchinatto WM; Sao Carlos Institute of Chemistry, University of Sao Paulo, Av. Trabalhador sao-carlense 400, CEP 13566-590, Caixa Postal 780, Sao Carlos, SP, Brazil. Electronic address: williamfacchinatto@usp.br., Dos Santos Garcia RH; Sao Carlos Institute of Chemistry, University of Sao Paulo, Av. Trabalhador sao-carlense 400, CEP 13566-590, Caixa Postal 780, Sao Carlos, SP, Brazil., Dos Santos DM; Brazilian Corporation for Agricultural Research, Embrapa Instrumentation, Rua XV de Novembro 1452, CEP 13560-970, Caixa Postal 741, Sao Carlos, SP, Brazil., Fiamingo A; Sao Carlos Institute of Physics, University of Sao Paulo, Av. Trabalhador sao-carlense 400, CEP 13566-590, Caixa Postal 369, Sao Carlos, SP, Brazil., Menezes Flores DW; Superior College of Agriculture 'Luiz de Queiroz', University of Sao Paulo, Av. Padua Dias 11, CEP 13418-900, Caixa Postal 9, Piracicaba, SP, Brazil., Campana-Filho SP; Sao Carlos Institute of Chemistry, University of Sao Paulo, Av. Trabalhador sao-carlense 400, CEP 13566-590, Caixa Postal 780, Sao Carlos, SP, Brazil., de Azevedo ER; Sao Carlos Institute of Physics, University of Sao Paulo, Av. Trabalhador sao-carlense 400, CEP 13566-590, Caixa Postal 369, Sao Carlos, SP, Brazil., Colnago LA; Brazilian Corporation for Agricultural Research, Embrapa Instrumentation, Rua XV de Novembro 1452, CEP 13560-970, Caixa Postal 741, Sao Carlos, SP, Brazil.
Jazyk: angličtina
Zdroj: Carbohydrate polymers [Carbohydr Polym] 2021 Mar 15; Vol. 256, pp. 117576. Date of Electronic Publication: 2020 Dec 30.
DOI: 10.1016/j.carbpol.2020.117576
Abstrakt: Chitosans with different average degrees of acetylation and weight molecular weight were analyzed by time-domain 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- 13 C dipolar interaction. RK-ROSE data were modeled by using Partial Least Square (PLS) multivariate regression, which showed a high coefficient of determination (R 2 > 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.
(Copyright © 2020 Elsevier Ltd. All rights reserved.)
Databáze: MEDLINE
Externí odkaz: