Graphite electrodes modified by 8-hydroxyquinolines and its application for the determination of copper in trace levels

Surface modification by 8-hydroxyquinoline-5-sulfonic acid (8-HQS) or 8-hydroxyquinoline (8-HQ) on a graphite electrode through irreversible adsorption is reported in this paper. Cyclic voltammetry was used to characterize the surface behavior. The modified surface exhibited an affinity to chelating...

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Bibliographic Details
Published in:Journal of the Brazilian Chemical Society 2006-01, Vol.17 (1), p.177-183
Main Authors: Sousa, Eliane R. de, Marques, Edmar P., Fernandes, Elizabeth N., Zhang, Jiujun, Marques, Aldaléa L. B.
Format: Article
Language:English
Subjects:
8-hydroxyquinoline
8-hydroxyquinoline-5-sulfonic acid
CHEMISTRY, MULTIDISCIPLINARY
stripping voltammetry
surface complex
trace copper determination
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Summary:Surface modification by 8-hydroxyquinoline-5-sulfonic acid (8-HQS) or 8-hydroxyquinoline (8-HQ) on a graphite electrode through irreversible adsorption is reported in this paper. Cyclic voltammetry was used to characterize the surface behavior. The modified surface exhibited an affinity to chelating Cu(II) in the solution, forming a Cu(II) complex, which was employed for Cu(II) trace analysis. Of the metals Zn, Ni, Pb, Co, and Cd, none presented interference until excess concentration of 10 times. Significant interference could be observed from Co(II), Cd(II) and Fe(II) for an excess concentration of 100 times on the analyte. A differential pulse voltammetry, combined with a preconcentrating-stripping process and a standard addition method was used for the analysis. A detection limit for trace copper determination in water, such as 5.1 ´ 10-9 mol L-1, was obtained.
ISSN:0103-5053
1678-4790
1678-4790
DOI:10.1590/S0103-50532006000100025