Carbon sensor electrode and process for producing the same

Abstract

A carbon electrode is dipped in a solution containing a reactive substance, and the carbon electrode impregnated with the solution is covered with an insulating tubular member; or a solution containing a reactant is poured into an insulating tube, and a carbon electrode is inserted into the tube; whereby the reactant is made coexistent in the periphery of the carbon electrode. Alternatively, a reactive substance such as an active enzyme and graphite particles or activated carbon particles are mixed with a liquid and dispersed therein to prepare a thoroughly wetted paste. The paste is introduced by means of an extruding mechanism such as a syringe into an insulating tubular member in which a bundle of many thin carbon rods as a lead is inserted. Thus, a carbon sensor electrode is produced. Alternatively, a first carbon electrode that has been dipped in an active enzyme or an enzyme-like reactive substance solution is disposed in a wet condition in a cylindrical ion permeable membrane. To prevent the enzyme or enzyme-like reactive substance in the electrode from becoming deactivated with the passage of time, a preliminary electrode is further inserted into the insulating tubular member, whereby the potential can be kept to be oxidation or reduction potential so as to ensure a constant sensor life. A fresh electrode surface having the active enzyme or enzyme-like reactive substance can be easily obtained by cutting or snapping off a tip portion of the sensor including the insulating tubular member.