Estudo polarografico de Fe(III) e Cu(II) em diversas matrizes utilizando eletrolito de suporte a base de citrato e EDTA

AUTOR(ES)
DATA DE PUBLICAÇÃO

2001

RESUMO

The polarographic determination of Fe(lll) in the presence of different species, including Cu(II), shows a characteristic: the overlapping of the peak potential of the Fe(lll) with the peak potentials of the other species. This interference can be eliminated through the addition of complexing agents like citrate, which cause the dislplacing of these potentials; however, the interference related to the Cu(ll) can only be eliminated with the addition of EDTA, which make possible the determination of both species. The best conditions for the study of Fe(lll) in the presence of Cu(ll) were obtained through the supporting electrolyte citrate 0,25 mol.L, EDTA 0,05 mol.L, KNO3 0,50 mol.L, pH 5,0. Matrices that have both iron and copper, as brass and some classes of vitamin and mineral salts, were used in the application of this supporting electrolyte. The differential pulse polarography was the analytical technique used in the determination of these metalic ions. The peak potentials observed for the Fe(lll) and for the Cu(ll) were, respectively, around -50 mV and -300 mV vs. Ag/AgCI (satureted KCI). Through the standard addition method was carried out the quantitative determination of the samples of iron and copper studied; in some medicine tablets were possible to realize the simultaneous determination of both species. The validation of the analytical method by the recuperation test showed values that express the applicability of the method in these analysis.

ASSUNTO(S)

complexos metalicos de transição polarografia quimica analitica

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