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

• Autor(a) principal: Yamashita,Miyuki
• Data de Publicação: 2002
• Outros Autores: Rosatto,Simone S., Kubota,Lauro T.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Journal of the Brazilian Chemical Society (Online)
• Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0103-50532002000500015
• topic: flavin; carbon paste electrode; silica gel; 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 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.