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Type: Artigo de periódico
Title: SiO2/Nb2O5 sol-gel as a support for HRP immobilization in biosensor preparation for phenol detection
Author: Rosatto, SS
Sotomayor, PT
Kubota, LT
Gushikem, Y
Abstract: A SiO2/Nb2O5 mixed oxide was prepared by a sol-gel processing method based on TEOS and NbCl5 as precursors and HCl as catalysts. A material having a specific surface area of 703 m(2) g(-1), average pore diameter of 2.4 nm and 5 wt.% of Nb was obtained. An amperometric peroxidase-based biosensor for phenol was constructed by immobilizing the enzyme onto the SiO2/Nb2O5 sol-gel matrix by adsorption and cross-linking with glutaraldehyde and mixing with graphite powder to make a modified carbon paste. The biosensor performance for phenol detection, investigated in a flow injection system, was based on mediated electron transfer of horseradish peroxidase (HRP), avoiding the direct electron transfer of HRP, which was blocked by the sol-gel matrix. With optimized conditions, a linear response range from 5 to 25 mumol dm(-3) for phenol was obtained with a sensitivity of 3.2 nA dm(3) mumol(-1). The detection limit of the biosensor for phenol was 0.5 mumol dm(-3) and the analytical frequency was 27 samples h(-1). The biosensor response was tested for various phenol substrates and the highest response was observed for 2-amino-4-chlorophenol. During 200 determinations, the biosensor kept the same response for phenol. The modified carbon paste retained its activity during 6 months of storage under refrigeration. (C) 2002 Elsevier Science Ltd. All rights reserved.
Subject: SiO2/Nb2O5 sol-gel
HRP enzyme
phenol compounds
amperometric biosensor
modified paste carbon electrode
Country: Inglaterra
Editor: Pergamon-elsevier Science Ltd
Rights: fechado
Identifier DOI: 10.1016/S0013-4686(02)00516-9
Date Issue: 2002
Appears in Collections:Unicamp - Artigos e Outros Documentos

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