Please use this identifier to cite or link to this item: http://repositorio.unicamp.br/jspui/handle/REPOSIP/102404
Type: Artigo de periódico
Title: Electrochemical Study Of Meldola's Blue, Methylene Blue And Toluidine Blue Immobilized On A Sio2/sb2o3 Binary Oxide Matrix Obtained By The Sol-gel Processing Method
Author: Ribeiro E.S.
Rosatto S.S.
Gushikem Y.
Kubota L.T.
Abstract: SiO2/Sb2O3 (SiSb), having a specific surface area, SBET, of 788 m2 g-1, an average pore diameter of 1.9 nm and 4.7 wt% of Sb, was prepared by the sol-gel processing method. Meldola's blue (MeB), methylene blue (MB) and toluidine blue (TB) were immobilized on SiSb by an ion exchange reaction. The amounts of the dyes bonded to the substrate surface were 12.49, 14.26 and 22.78 μmol g -1 for MeB, MB and TB, respectively. These materials were used to modify carbon paste electrodes. The midpoint potentials (Em) of the immobilized dyes were -0.059, -0.17 and -0.18 V vs. SCE for SiSb/MeB, SiSb/MB and SiSb/TB modified carbon paste electrodes, respectively. A solution pH between 3 and 7 practically did not affect the midpoint potential of the immobilized dyes. The electrodes presented reproducible responses and were chemically stable under various oxidation-reduction cycles. Among the immobilized dyes, MeB was the most efficient to mediate the electron transfer for NADH oxidation in aqueous solution at pH 7. In this case, amperometric detection of NADH at an applied potential of 0 mV vs. SCE gives linear responses over the concentration range of 0.1-0.6 mmol L-1, with a detection limit of 7 μmol L-1.
Editor: 
Rights: fechado
Identifier DOI: 10.1007/s10008-003-0368-x
Address: http://www.scopus.com/inward/record.url?eid=2-s2.0-0242521727&partnerID=40&md5=93dd05fa3bb1da0bf9e55fc6e4508f25
Date Issue: 2003
Appears in Collections:Unicamp - Artigos e Outros Documentos

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