Prussian Blue-based 'artificial peroxidase' as a transducer for hydrogen peroxide detection. Application to biosensors

The present investigation of a novel electrochemical transducer is defined by the requirements of the one of the most significant fields of modern ana lytical biotechnology, i.e., electrochemical biosensors. Prussian Blue, whi ch has been deposited on the surface of glassy carbon electrode under certa in conditions, was found to be a selective electrocatalyst for H2O2 reducti on in the presence of O-2. In its reduced form (Prussian White) the inorgan ic polycrystal is known to be partially soluble in aqueous solution. To sta bilize the electrocatalyst at cathodic potentials and preventing loss from the electrode surface, an independent investigation was performed. As a res ult, a completely stable electrocatalyst was achieved. The kinetics of H2O2 reduction onto the surface of Prussian Blue modified electrodes was invest igated. Due to the high catalytic activity and selectivity which were compa rative with biocatalysis, the specially deposited Prussian Blue was denoted as 'artificial peroxidase'. The biosensors were made by enzyme immobilizat ion on the top of the Prussian Blue modified electrodes. The electrochemica l transducer and biosensors were suitable for detection of low analyte leve ls and were practically independent of potentially interfering reductants. (C) 1999 Elsevier Science S.A. All rights reserved.