IMMOBILIZED XANTHINE OXIDASE WITH BIO-COMPOSITE USING GAS BIOSENSOR

The paper describes the development of biosensor for gas detection using bio-composite-xanthine oxidase. The xanthine oxidase enzyme is immobilized by bio-composite including gelatine and chitosan. The high stability of immobilization enzymes onto a solid substrate can make them ideal alternatives as recognition elements for sensors. Xanthine oxidase was constructed in a very simple way using ammonium sulfate precipitation and affinity chromatography. Xanthine oxidase was immobilized with bio-composite on glass and quartz crystal substrates. The structural properties of bio-composite films have been investigated via ultraviolet visible spectrophotometer and quartz crystal microbalance systems. In order to investigate the sensing properties of bio-composite films, five vapors such as chloroform, acetone, toluene, ethyl acetate and carbon tetrachloride were selected and quartz crystal micro balance system were employed to characterize the sensing properties. Results were remarkable that the bio-composite gas sensor showed selective and reproducible responses against organic vapors. The gas sensor can be used for application in the monitoring and screening of diabetes through the detection of low concentrations of breath acetone vapor.