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 analytical biotechnology, i.e., electrochemical biosensors. Prussian Blue, which has been deposited on the surface of glassy carbon electrode under certain conditions, was found to be a selective electrocatalyst for H2O2 reduction in the presence of O-2. In its reduced form (Prussian White) the inorganic polycrystal is known to be partially soluble in aqueous solution. To stabilize the electrocatalyst at cathodic potentials and preventing loss from the electrode surface, an independent investigation was performed. As a result, a completely stable electrocatalyst was achieved. The kinetics of H2O2 reduction onto the surface of Prussian Blue modified electrodes was investigated. Due to the high catalytic activity and selectivity which were comparative with biocatalysis, the specially deposited Prussian Blue was denoted as 'artificial peroxidase'. The biosensors were made by enzyme immobilization on the top of the Prussian Blue modified electrodes. The electrochemical transducer and biosensors were suitable for detection of low analyte levels and were practically independent of potentially interfering reductants. (C) 1999 Elsevier Science S.A. All rights reserved.