Electrochemical study of ferrocene intercalated vanadium pentoxide xerogel/polyvinyl alcohol composite films: Application in the development of amperometric biosensors

A detailed electrochemical study of a novel composite film based on ferrocene intercalated vanadium pentoxide xerogel/polyvinyl alcohol (FeCp2/VXG PVA-SbQ) and its potential use in the development of amperometric biosensors is presented. FeCp2-VXG was characterized with X-ray powder diffraction, Mossbauer spectroscopy, energy dispersive spectroscopy and IR-spectroscopy suggesting a molecular formula close to (FeCp2)(0.37)center dot V2O5 center dot nH(2)O. Composite films of (FeCp2)(0.37)center dot V2O5 center dot nH(2)O with PVA-SbQ were developed over a glassy carbon electrode. Cyclic voltammetry experiments showed that composite films exhibit reversible, almost charge-transfer controlled redox functions. The influence of various buffering systems composition on the working stability of the so modified electrodes was also investigated. Redox films were further modified by immobilizing glucose oxidase as a model enzyme. A remarkable electrocatalytic effect of the intercalated FeCp2 towards the reduced form of the enzyme cofactor (FAD-H-2) was observed. Under optimized conditions, glucose biosensor was mounted into a flow injection analysis manifold and found to yield a linear response up to 10 mM glucose. (C) 2005 Elsevier B.V. All rights reserved.