Glucose Biosensor Prepared by the Deposition of Iridium and Glucose Oxidase on Glassy Carbon Transducer

A first generation glucose biosensor based on the electrodeposition of iridium and glucose oxidase (GOx) on pretreated glassy carbon is described. The strong electrocatalytic action of iridium towards hydrogen peroxide allows fast glucose quantification at very low potentials where the interference of easily oxidizable compounds such as ascorbic and uric acids is minima. The influence of electrode pretreatment, plating solution composition and deposition time on the analytical performance and kinetic behavior of the bioelectrodes is studied. In all the cases the bioelectrodes response was measured using hydrogen peroxide and glucose in order to evaluate how the experimental conditions affect both iridium and GOx deposition. A long-term stability study showed that the sensitivity remains around 60% of its original value up to forty-five days. The results demonstrated that the diminution in the activity of the bioelectrode is due to the decrease in the biocatalytic activity and not to iridium leaching. The bioelectrodes were used for measuring the glucose content in a commercial physiological solution and the results showed a relative error of 6.0 % with the label claim.