Fabrication and characterisation of novel screen-printed tubular microband electrodes, and their application to the measurement of hydrogen peroxide

A new method of using screen-printed carbon electrodes (SPCEs) incorporating the electrocatalyst cobalt phthalocyanine (CoPC) for the manufacture of tubular microband electrodes for hydrogen peroxide detection is described. Characterisation of these electrodes using potassium ferrocyanide, with cyclic voltammetry, has shown that steady state behaviour is displayed which is indicative of microelectrode behaviour. The current density obtained from the voltammogram was compared to that obtained for a conventional sized CoPC-SPCE, and the values were 5618 and 35.65 mu A cm(-2), respectively. Cyclic voltammetry was carried out for the same electrodes, using 7 mM H2O2 prepared in phosphate buffer at scan rates between 1 and 50 mV s(-1) and no significant increase in current response was observed. The application of these tubular microband CoPC-SPCEs, to the measurement of H2O2 using chronoamperometry was investigated. A calibration study was performed and the plot showed a sensitivity value of 252 mu A mM(-1) cm(-2) and a lower detection limit of 70 mu M. We have shown that the chronoamperometric current response could be calculated using a modified equation originally developed for a plain microband electrode. This study provides a platform for using screen-printed carbon electrodes for the fabrication of oxidase based microbiosensors, for the determination of a variety of cellular metabolites. (C) 2007 Elsevier Ltd. All rights reserved.