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

Measuring the solubility product constant of paramagnetic cations using time-domain nuclear magnetic resonance relaxometry

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Author(s):
Cobra, Paulo Falco [1] ; Gomes, Bruna Ferreira [1] ; Nascimento Mitre, Cirlei Igreja [1] ; Barbosa, Lucio Leone [2] ; Marconcini, Lucineia Vizzotto [3] ; Colnago, Luiz Alberto [4]
Total Authors: 6
Affiliation:
[1] Univ Sao Paulo, Inst Quim Sao Carlos, Sao Carlos, SP - Brazil
[2] Univ Fed Espirito Santo, Dept Quim, Vitoria, ES - Brazil
[3] Univ Estadual Paulista, Inst Quim, Araraquara, SP - Brazil
[4] Embrapa Instrumentacao, BR-13560970 Sao Carlos, SP - Brazil
Total Affiliations: 4
Document type: Journal article
Source: Microchemical Journal; v. 121, p. 14-17, JUL 2015.
Web of Science Citations: 11
Abstract

The use of time-domain NMR relaxometry is already well established for determining the concentration of paramagnetic cations. Paramagnetic cations have unpaired electrons, and in aqueous solutions, they interact with hydrogen nuclei, changing the relaxation time of the solvent. Thus, a linear relationship can be established between the nuclear spin-lattice relaxation time, T-1, or the spin-spin relaxation time, T-2, and the concentration of paramagnetic ions in solution. Previous studies have shown the efficacy of using T-1 and T-2 for easily determining the titration equivalence point. Currently, the most practical method for determining T-2 is the Carr-Purcell-Meiboom-Gill (CPMG) pulse sequence. Thus, in this paper, we used the T-2 relaxation time to determine the concentration of paramagnetic ions in solution. We used T-2 relaxometry as a simple and useful method for measuring the hydroxide solubility products (K-sp) of Fe(OH)(3), Cu(OH)(2) and Mn(OH)(2) aqueous solutions as functions of pH. To our knowledge, this is the first use of T-2 relaxometry to measure K-sp. (C) 2015 Elsevier B.V. All rights reserved. (AU)

FAPESP's process: 12/22281-9 - NMR study of the magneto-convective phenomenon on paramagnetic ions during electrodeposition
Grantee:Bruna Ferreira Gomes Lobo
Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
FAPESP's process: 12/20247-8 - Development and validation of time domain NMR spectrometers and methods for non-destructive analysis of food
Grantee:Luiz Alberto Colnago
Support Opportunities: Regular Research Grants