Organic layers via aryl diazonium electrochemistry: towards modifying platinum electrodes for interference free glucose biosensors

Although oxidases are selective and specific biocatalysts frequently used in enzyme biosensors, amperometric detection methods can hardly distinguish the current response of enzymatic reaction products from the currents generated by other electroactive species commonly encountered in complex matrices. Therefore, various methods have been developed in order to improve the overall selectivity of enzyme-based biosensors. Here, we employ substituted polyaryl films grafted on platinum electrodes via the electrochemical reduction of a variety of diazonium tetrafluoroborates as blocking layers. Electron transfer kinetics of three redox probes at the bare and modified Pt electrodes were investigated in order to evaluate the blocking effect of the grafted layers. Further, the effect of surface modification on the voltammetric responses of commonly encountered interferents for glucose determination were examined. As proof of concept, interference-free amperometric biosensors employing glucose oxidase were constructed using aryl modified Pt electrodes.