Advanced search
Start date
(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Rapid method for monitoring chitosan coagulation using low-field NMR relaxometry

Full text
Crizostomo Kock, Flavio Vinicius [1] ; Colnago, Luiz Alberto [2]
Total Authors: 2
[1] Univ Sao Paulo, Inst Quim Sao Carlos, Ave Trabalhador Sao Carlense 400, BR-13566590 Sao Carlos, SP - Brazil
[2] Embrapa Instrumentacao, Rua 15 Novembro 1452, BR-13560970 Sao Carlos, SP - Brazil
Total Affiliations: 2
Document type: Journal article
Source: Carbohydrate Polymers; v. 150, p. 1-4, OCT 5 2016.
Web of Science Citations: 5

Time-domain NMR relaxometry was proposed as a simple, rapid method to monitor chitosan (CS) coagulation as a function of pH. The longitudinal (T-1) and transverse (T-2) relaxation times of three CS concentrations (0.022, 0.22, and 2.2 g L-1) were simultaneously measured by CP-CWFPx-x pulse sequences in a 0.47T spectrometer. T-1 and T-2 were shown to be independent of pH as well as to assume values similar to the relaxation time of water (2.7 s) at the lowest tested CS concentration. At the highest concentration, T-1 increased whereas T-2 decreased as pH varied from 6.0 to 7.0. This indicates a remarkable effect of CS on water relaxation at pH values higher than the pKa of CS amino groups (6.5). Therefore, CS reduced the water mobility at the highest CS concentration and greatest pH values, suggesting a CS supramolecular structure (gel) that entraps the solvent in confined regions. The method proposed here can be further used to study the coagulation of other polysaccharides. (C) 2016 Elsevier Ltd. All rights reserved. (AU)

FAPESP's process: 14/22126-9 - Development of time domain NMR spectrometers and methods for chemical analyses in field
Grantee:Luiz Alberto Colnago
Support type: Regular Research Grants
FAPESP's process: 12/23169-8 - In situ study of action of quitosan biopolymer in the decontamination of metals and herbicides in aqueous system by electrochemistry coupled to high and low field NMR
Grantee:Flavio Vinicius Crizostomo Kock
Support type: Scholarships in Brazil - Doctorate