Please use this identifier to cite or link to this item: http://repositorio.unicamp.br/jspui/handle/REPOSIP/82531
Type: Artigo de periódico
Title: Estudo comparativo da seletividade de um método cinético-catalítico: a determinação de Cr(VI) pela oxidação da o-dianisidina pelo peróxido de hidrogênio
Title Alternative: Comparative study of the selectivity of a kinetic-catalytic method: the determination of Cr (VI) by oxidation of the o-dianisidine by hidrogen peroxide
Author: Reis, César
Andrade, João Carlos de
Bruns, Roy Edward
Abstract: Selectivity studies for the determination of Cr(VI) using the catalytic oxidation of the o-dianisidine by hydrogen peroxide showed two distincts situations. In the first, when interferents were studied by a univariate procedure, Cr(III) and Cu(II) cause serious interferences even at the 2:1 proportion, relative to Cr(VI), while Fe(III) interfered at the 15:1 ratio and EDTA at the 10:1 ratio. On the other hand, when a multivariate investigation was performed, Cr(III) did not present any significant principal effects and its significant interaction effects were negative, in contrast to EDTA, that presented positive interaction effects although, like Cr(III), did not show significant interaction effects. In view of the interferent's action it become necessary to separate Cr(VI) by extraction with methylisobutylketone in a chloridric acid medium before its determination in vegetals and in wastewater from a cellulose industry samples. Using this procedure, the method precision is ±0,5% at the 10 ng/mL Cr(VI) concentration level. The detection and quantification limits, calculated by means of absorbance measurements of ten replicates of blank reagents were 1,1 and 3,2 ng/mL, respectively. The results obtained with real samples showed a relative standard deviation between 1,2% and 3,0% relative to their reference values.
Subject: selectivity
kinetic method
experimental design
Editor: Sociedade Brasileira de Química
Rights: aberto
Identifier DOI: 10.1590/S0100-40421999000200008
Address: http://dx.doi.org/10.1590/S0100-40421999000200008
http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-40421999000200008
Date Issue: 1-Apr-1999
Appears in Collections:Artigos e Materiais de Revistas Científicas - Unicamp

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