OXYDASE ELECTRODE

PURPOSE:To make direct measurement of a substrate concn. by supplying necessary O2 constantly from one side to the other side of an electrode having porous structure and amperometrically measuring the H2O2 generated by immobilized oxidase. CONSTITUTION:An enzyme electrode is constituted of a gas permeable film 5 which is held in contact with one face of the electrode 6 having the porous structure, a gas chamber isolated by the permeable film 5, an immobilized oxidase enzyme layer 7 which exists on another face of the electrode, and a permeable film 8 of the oxidase substrate which coats the outside surface thereof. A voltage at which the H2O2 is oxidized is impressed to the electrode 6. A silver/silver chloride electrode, platinum electrode, etc., are used for a counter electrode. Air or gaseous oxygen is pressurized usually to 1atm, more preferably to >=1atm in the gas chamber. The gas permeable film is film having permeability of O2 and is disposed in contact with one face of the electrode. An enzyme soln. is dropped or coated onto the other face of the electrode and the solvent is evaporated to immobilize the enzyme to the electrode surface. A nitrocellulose film, permeable film, etc. are usable as the substrate permeable film.