TETRATHIAFULVALENE-MEDIATED BIOSENSOR FOR L-LACTATE IN DAIRY-PRODUCTS

A tetrathiafulvalene (TTF)-mediated, amperometric biosensor was develo ped for the specific determination of L-lactate. L-lactate oxidase was immobilized by adsorption and retained on the surface of a carbon-pas te electrode using an electro-polymerized film of 1,3-phenylenediamine resorcinol. The response of the biosensor was maximum at pH 7.0 and 30 degrees C. Response was linear up to 0.6 mM lactate and had a minimum detection limit of 56 mu M. Response time was less than 90 sec. When stored at 4 degrees C response was stable for > 36 days and subsequent ly decreased. The sensor was unresponsive after 96 days. This enzyme-b ased biosensor was suitable for determining lactate concentrations in milk and yogurt.