Potentiometric biosensor based on immobilized enzyme membrane and fluoride detection

Abstract

This paper describes two new potentiometric biosensors that combine the selectivity of an immobilized enzyme membrane and the sensitivity of fluoride ion detection. The principle of these biosensors is based on the reaction of 4-fluorophenol with hydrogen peroxide, catalyzed by immobilized peroxidase, to produce fluoride ion, which is measured potentiometrically by a fluoride electrode. By coupling this reaction with other oxidases that produce hydrogen peroxide, sensitive sensors for substrates of these oxidases can be obtained. Potentiometric biosensors for hydrogen peroxide and glucose using immobilized peroxidase and immobilized peroxidase/glucose oxidase membranes, respectively, were developed. The preparation of immobilized enzyme membranes, optimal conditions of operation, and performance of these biosensors are described.