AMPEROMETRIC BIOSENSOR FOR DETERMINATION OF LACTATE IN SWEAT

An amperometric hydrogen peroxide based biosensor has been developed for non-invasive determination of L-lactate. The biosensor utilizes lactate oxidase immobilized between a polycarbonate membrane and a polytetrafluoroethylene (PTFE) blocking membrane to effectively eliminate electrochemical interferences. Both the steady state current and maximum rate of current change were measured. The response times were 2 min and 10 s, respectively. Because of the addition of polycarbonate and PTFE 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 applied to the analysis of sweat L-lactate content of healthy subjects during physical exercise.