A new amperometric glucose biosensor based on screen printed carbon electrodes with rhenium(IV) - oxide as a mediator

Abstract

Rhenium(IV)-oxide, ReO 2 , was used as a mediator for carbon paste (CPE) and screen printed carbon (SPCE) electrodes for the catalytic amperometric determination of hydrogen peroxide, whose overpotential for the reduction could be lowered to -0.1 V vs. Ag/AgCl in flow injection analysis (FIA) using phosphate buffer (0.1 M, pH=7.5) as a carrier.For hydrogen peroxide a detection limit (3σ) of 0.8 mg L -1 could be obtained.ReO 2 -modified SPCEs were used to design biosensors with a template enzyme, i.e. glucose oxidase, entrapped in a Nafion membrane.The resulting glucose sensor showed a linear dynamic range up to 200 mg L -1 glucose with a detection limit (3σ) of 0.6 mg L -1 .The repeatability was 2.1 % RSD (n = 5 measurements), the reproducibility 5.4 % (n = 5 sensors).The sensor could be applied for the determination of glucose in blood serum in good agreement with a reference method.