Tetrathiafulvalene-mediated Biosensor for L-lactate in Dairy Products

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