โ Scribed by Shigeru Yamauchi; Masashi Yaoita; Futoshi Matsumoto; Takahiro Yokoyama; Yoshihito Ikariyama
No coin nor oath required. For personal study only.
An enzyme embodied electrode (EEE) is an electrochemical biosensing device fabricated by direct immobilization of enzyme on a platinized electrode. In order to elucidate the reaction scheme of an EEE, the pulse voltammettic technique wris employed, in which a potentiostatic pulse was applied after the preoxidation pulse and the following open circuit period, sequentially. A reaction scheme was proposed hy taking substrate and product diffusion in the micropores of platinum black into account, besides the enzymatic and electrochemical reactions. During the open circuit period the concentration profile of hydrogen peroxide was assumed to reach a steady state when the production of hydrogen peroxide equilibrated with the diffusion at the microporous electrode. Assuming a steady state concentration profile at the balanced state, an appropriate solution was deduced for a differential equation that expresses enzymatic production, electrochemical oxidation and diffusion of hydrogen peroxide to bulk solution. This expression explained well the observed transient current that decayed exponentially and the proportionality to the glucose concentration.
๐ SIMILAR VOLUMES
An amperometric enzyme electrode for the detection of bile acids using 3-a-hydroxysteroid dehydrogenase coupled to an N-methyl phenazinium tetracyanoquinodimethanide electrode @IMPTCNQ) is described. Kinetic analysis shows that the rate limiting step is the transport of substrate through the membran
A urea enzyme microsensor was fabricated by immobilizing urease at the tip (lo-rm diameter) of a rapidly responding ammonia gas microelectrode based on antimony. The construction and evaluation of both the urea sensor and the ammonia electrode are described in detail. The urea sensor responds to lo-