Electrocatalysis and Amperometric Detection of Hydrogen Peroxide at an Aluminum Microelectrode Modified with Cobalt Hexacyanoferrate Film

 The electrocatalytic activity of an aluminum microelectrode modified with cobalt hexacyanoferrate film is described. A simple method was used for the preparation of the modified microelectrode. The modified microelectrode exhibits good electrocatalytic properties for electrochemical reduction of hydrogen peroxide. The effect of solution pH and applied potential on the electrocatalytic properties of the modified microelectrode is investigated. The results show that the best potential for the detection of hydrogen peroxide is 0.0 vs. SCE for better response and decrease of interferences. Due to the microelectrode scale, it can be used for the determination of small amounts of H₂O₂. The calibration plot is linear up to 1.7 mM (r = 0.988) with a response time of 5.1 s. The detection limit of the microelectrode as H₂O₂ sensor is 2 × 10⁻⁷ M. The sensivity of the H₂O₂ sensor is 225.6 nA mmol⁻¹ and RSD of this sensor is less than 2.3%. In addition, effects of possible interferences and possibility of the sensor for real samples is investigated. The present work shows the potential of the proposed method for the fabrication of modified electrodes, as it can be used to employ for different purposes in micro scale. Received June 20, 2001; accepted June 14, 2002