Electrochemical Comparative Study of Riboflavin, FMN and FAD Immobilized on the Silica Gel Modified with Zirconium Oxide

Modified carbon paste electrodes were prepared by the adsorption of flavin on a silica gel modified with zirconium oxide (Si:Zr:flavin). The electrochemical behavior of immobilized riboflavin, FMN and FAD was investigated. The formal potentials, Eº´, for the flavins in these electrodes were found to...

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Veröffentlicht in:Journal of the Brazilian Chemical Society 2002-09, Vol.13 (5), p.635-641
Hauptverfasser: Yamashita, Miyuki, Rosatto, Simone S., Kubota, Lauro T.
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Sprache:eng
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Zusammenfassung:Modified carbon paste electrodes were prepared by the adsorption of flavin on a silica gel modified with zirconium oxide (Si:Zr:flavin). The electrochemical behavior of immobilized riboflavin, FMN and FAD was investigated. The formal potentials, Eº´, for the flavins in these electrodes were found to be -0.46 V vs. SCE, this being similar to their values obtained in solution. Their Eº´ values remained pH dependent with certain invariance for riboflavin between 4 and 5. The composition of the supporting electrolyte did not affect the Eº´ with exception of Ca2+, but in buffer systems and especially in phosphate a good rate of electron transfer was observed. The differences verified in the electrochemical behavior and UV-visible absorption spectra among the immobilized flavins are discussed in terms of different kinds of interaction.
ISSN:0103-5053
1678-4790
DOI:10.1590/S0103-50532002000500015