Sol–gel-based amperometric glucose biosensor incorporating an osmium redox polymer as mediator

Abstract

A novel amperometric biosensor for the determination of glucose was constructed by first immobilizing glucose oxidase and an osmium redox polymer, [Os(bpy)₂(PVP)₁₀Cl]Cl, on the surface of a glassy-carbon electrode, followed by coating with a sol–gel film derived from methyltriethoxysilane. The redox potential of this electrode was found to be +247 mV versus Ag/AgCl, and glucose could therefore be determined amperometrically at +400 mV versus Ag/AgCl. The concentration range of linear response, slope of linear response and LOD were 2.0–31 mmol l^–1, 44.5 nA mmol^–1 l and 0.5 mmol. l^–1, respectively. Although L-ascorbate was electrooxidizable at this potential, uric acid and paracetamol were both found not to interfere.