Please use this identifier to cite or link to this item: http://repositorio.unicamp.br/jspui/handle/REPOSIP/23463
Type: Artigo de periódico
Title: Aplicação de métodos quimiométricos na especiação de Cr(VI) em solução aquosa
Title Alternative: Chemometric methods applied to the speciation of aqueous Cr(VI) solutions
Author: Sena, Marcelo M.
Collins, Carol H.
Collins, Kenneth E.
Scarminio, Ieda S.
Abstract: The equilibria, the spectra and the identities of the species of Cr(VI) that are present in aqueous solution have long been an active subject of discussion in the literature. In this paper, three different chemometric methodologies are applied to sets of UV/Visible spectra of aqueous Cr(VI) solutions, in order to solve a chemical system where there is no available information concerning the composition of the samples nor spectral information about the pure species. Imbrie Q-mode factor analysis, followed by varimax rotation and Imbrie oblique projection, were used to estimate the composition of Cr(VI) equilibrium solutions and, by combining these results with the k-matrix method, to obtain the pure spectra of the species. Evolving factor analysis and self modeling curve resolution were used to confirm the number of the species and the resolution of the system, respectively. Sets of 3.3×10-4 and 3.3×10-5 mol L-1 Cr(VI) solutions, respectively, were analyzed in the pH range from 1 to 12. Two factors were identified, which were related to the chromate ion (CrO4(2-)) and bichromate ion (HCrO4-). The pK of the equilibrium was estimated as 5.8.
Subject: chromium(VI)
chemometrics
Imbrie Q-mode factor analysis
evolving factor analysis
self modeling curve resolution
equilibrium pK
Editor: Sociedade Brasileira de Química
Rights: aberto
Identifier DOI: 10.1590/S0100-40422001000300009
Address: http://dx.doi.org/10.1590/S0100-40422001000300009
http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-40422001000300009
Date Issue: 1-Jun-2001
Appears in Collections:Artigos e Materiais de Revistas Científicas - Unicamp

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