AMPEROMETRIC BIOSENSOR FOR DETERMINATION OF LACTATE IN SWEAT

An amperometric hydrogen peroxide based biosensor has been developed f or non-invasive determination of L-lactate. The biosensor utilizes lac tate oxidase immobilized between a polycarbonate membrane and a polyte trafluoroethylene (PTFE) blocking membrane to effectively eliminate el ectrochemical interferences. Both the steady state current and maximum rate of current change were measured. The response times were 2 min a nd 10 s, respectively. Because of the addition of polycarbonate and PT FE membranes, the linear range of lactate was extended up to 140 mg dl -1 and the apparent Michaelis-Menten constant was almost two orders of magnitude higher than that of the free enzyme. The biosensor was appl ied to the analysis of sweat L-lactate content of healthy subjects dur ing physical exercise.