SOL-GEL BASED AMPEROMETRIC BIOSENSOR INCORPORATING AN OSMIUM REDOX POLYMER AS MEDIATOR FOR DETECTION OF L-LACTATE

A novel amperometric biosensor for the determination of lactate was co nstructed by first immobilizing lactate oxidase and an osmium redox po lymer ([Os(bpy)(2)(PVP)(10)Cl]Cl; abbreviated Os-polymer) on the surfa ce of a glassy carbon electrode, followed by coating with a sol-gel fi lm derived from methyltriethoxysilane (MTEOS). The electrooxidation cu rrent of this electrode was found to be diffusion controlled. In the p resence of lactate, a clear electrocatalytic oxidation wave was observ ed, and lactate could be determined amperometrically at 400 mV versus Ag/AgCl. The concentration range of linear response, slope of linear r esponse and detection limit were 0.1-9 mM, 1.02 mu A mM(-1), and 0.05 mM, respectively. Although L-ascorbate was electrooxidized at this pot ential, uric acid, paracetamol and glucose were found not to interfere . (C) 1997 Elsevier Science B.V.