Please use this identifier to cite or link to this item: http://repositorio.unicamp.br/jspui/handle/REPOSIP/195413
Type: Artigo de periódico
Title: Electrochemical Behavior Of Pyrroloquinoline Quinone Immobilized On Silica Gel Modified With Zirconium Oxide.
Author: Yamashita, Miyuki
Pessôa, Christiana A
Kubota, Lauro T
Abstract: Pyrroloquinoline quinone (PQQ) was immobilized on the silica gel surface modified with zirconium oxide, designated as Si:Zr, by the carboxylic groups of the PQQ molecule and the zirconium oxide on the silica surface. The electrochemistry of PQQ immobilized on the Si:Zr matrix, incorporated in a carbon paste electrode, was evaluated using the cyclic voltammetry technique. The Si:Zr:PQQ-modified electrode showed a redox couple at E(m)=(E(pa1)+E(pc))/2=-0.150 V vs SCE at pH 7, close to that observed in aqueous solution, and another oxidation peak, E(pa2)=-0.100 V vs SCE. Studies in different pH solutions in the range of 3-7 showed that the first oxidation peak, E(pa1), is highly dependent on the solution pH shifting from to -0.175 to 0.100 V vs SCE, while E(pa2) remains practically constant at 0.100 V as the pH decreases from 7 to 3. The immobilized PQQ electrode presented the property to electrocatalyze the NADH at 150 mV vs SCE. The effect of addition of Ca(2+) ions on the electrode electroactivity for the NADH oxidation was also verified. Different from that observed for the PQQ immobilized on other electrode materials, the Ca(2+) ions did not influence the electrocatalytical response; however, the electrode stability was considerably improved in the presence of Ca(2+) ions, indicating that the matrix surface has a great influence on the electrochemical behavior of PQQ.
Subject: Benzoquinones
Calcium
Carbon
Electrochemistry
Hydrogen-ion Concentration
Ions
Models, Chemical
Nad
Pyrroles
Quinolines
Silicon Dioxide
Spectrophotometry
Ultraviolet Rays
Zirconium
Citation: Journal Of Colloid And Interface Science. v. 263, n. 1, p. 99-105, 2003-Jul.
Rights: fechado
Address: http://www.ncbi.nlm.nih.gov/pubmed/12804890
Date Issue: 2003
Appears in Collections:Unicamp - Artigos e Outros Documentos

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