Direct voltammetry of catalase immobilized on silica sol-gel and cysteine modified gold electrode and its application

The direct voltammetry of catalase (CAT) immobilized in silica sol-gel film in the presence of cysteine on gold electrode was investigated. The CAT electrode showed a pair of well-defined and quasi-reversible cyclic voltammetry peaks. It can be used as an electrochemical biosensor for the determination of hydrogen peroxide. The calibration range of H2O2 was from 1 to 30 mu mol L-1 and the detection limit was 0.4 mu mol L-1 at a signal-to-noise ratio of 3. The interaction of CAT and aluminum ion was also investigated based on the CAT-modified electrode. The electrochemical activity of the CAT-modified electrode was increased with the addition of Al3+. The experimental results of voltammetry and fluorescence spectroscopy indicated that the conformation of CAT molecule was altered by the formation of Al-CAT complex with Al3+, which may influence the activity of CAT. (c) 2006 Elsevier B.V. All rights reserved.