No abstract

International audienceA technique of immobilizing very thin layer of enzymes over glass electrodes, resulting in response times as low as 5-10s, is described. The method involves the adsorption of enzyme molecules onto the sensitive end of the glass electrode followed by the formation of covalent bonds between the enzyme molecules, by means of spraying a dilute solution of glutaraldehyde over the surface. Enzymes immobilized in this manner over pH glass elctrodes are acetylcholinesterase (AChE), butyrylcholinesterase (BuChE), penicillinase, and urease. The cross-sectional scanning electron micrograph of the fractured surface of the electrode shows the immobilized layer is not more than 1-2 µm thick. The technique could offer immense scope for immobilization of other protein substances as thin layers on different support surfaces

No abstract

No abstract

An enzyme immobilization technique has been developed to determine the concentration of biological compounds. This technique has been applied to penicillinase and urease, which are crosslinked as very fine films directly onto the sensitive ends of pH glass electrodes, thereby dispensing with the need of an on-line enzyme reactor. The biosensor is incorporated in an FIA system within a magnetically stirred detection cell. Penicillin-V in fermentation broth and urea in human serum samples were detected and the results were compared with HPLC and spectrophotometric methods. On-line measurement is achieved through the automation of this FIA system.