Abstract: The biosensor of the present invention quantifies a substrate contained in a sample liquid by reducing electron acceptors using electron generated in a reaction of the substrate to enzyme and then by measuring the reduced amount of the electron acceptors electrochemically. The biosensor has an electrical insulating substrate, an electrode system including at least a working electrode and a counter electrode, a reaction layer including the enzyme provided on the electrode system and a hydrogen ion concentration control layer, and the reaction layer is in contact with the electrode system. According to the present invention, the hydrogen ion concentration in the sample liquid can be made most appropriate in accordance with the type of the enzyme contained in the reaction layer, without the adjustment of the hydrogen ion concentration in the sample liquid beforehand. Thus, the specific substrate contained in the sample liquid can be easily quantified with accuracy and speed.

Abstract: This invention relates to a biosensor which comprises an insulative base, an electrode system formed on the substrate and primarily made of carbon, and a perforated body having an enzyme and an electron acceptor and integrally combined with the electrode system whereby a concentration of a specific component in a biological liquid sample can be electrochemically measured rapidly and accurately by a simple procedure of mere addition of the liquid sample. Several simple biosensors for measuring a specific component in a liquid sample are known including a sensor of the type in which a change of a dye formed by an enzyme reaction is optically detected and a sensor of the type using an enzyme electrode. These sensors, respectively, involve an interference with colored matters in liquid sample and necessity of washing of an electrode system every measuring procedure. In addition, the sensors are complicated in structure and materials therefor are expensive.

Abstract: As the conventional simple bio-sensors for measuring the particular component in living bodies, there are those in which a change in dye caused by enzyme reaction is detected optically, but such bio-sensors had a problem that precision is low owing to disturbance of the color of liquid samples. With bio-sensors using an enzyme electrode, the precision was high, but operation of measurement was troublesome. The present invention made it possible to detect the concentration of the particular component electromechanically with rapidity, simplicity and high precision by merely putting a porous substrate containing at least enzyme on the electrode system and impregnating the body with a liquid sample.

Abstract: A biosensor of the invention comprises an insulating base board (1) having formed thereon, in sequence, leads (2, 3, 3'), an electrode system mainly made of carbon (4, 5, 5'), an insulating layer (6) and a reaction layer (14) composed of an enzyme and an electron acceptor, and being provided thereon with a space (8) defined by a spacer (7) and a cover 9). When a biological sample solution is brought into contact with the inlet (10) of the biosensor having the above-described structure, the sample solution is introduced into its inside, while the air within the space (8) is rapidly discharged through the outlet (11) and, at the same time, the space (8) is filled with the sample solution up to the neighborhood of the outlet. Thus, measurement can be conducted inexpensively at a high speed with a high accuracy through simple procedures without residual bubbles.

Abstract: This invention relates to a biosensor which comprises an insulative base, an electrode system formed on the substrate and primarily made of carbon, and a perforated body having an enzyme and an electron acceptor and integrally combined with the electrode system whereby a concentration of a specific component in a biological liquid sample can be electrochemically measured rapidly and accurately by a simple procedure of mere addition of the liquid sample. Several simple biosensors for measuring a specific component in a liquid sample are known including a sensor of the type in which a change of a dye formed by an enzyme reaction is optically detected and a sensor of the type using an enzyme electrode. These sensors, respectively, involve an interference with colored matters in liquid sample and necessity of washing of an electrode system every measuring procedure. In addition, the sensors are complicated in structure and materials therefor are expensive.

Abstract: A rechargeable electrochemical device composed of a negative electrode (4) which comprises an alkali metal as an active material, a non-aqueous electrolyte (6), and a positive electrode (1). The positive electrode (1) is composed of an oxide of chromium and vanadium represented by the general formula:Cr.sub.x V.sub.2(1-x) O.sub.5-(2+y)x(wherein 0.2.ltoreq.x.ltoreq.0.9, 0.1.ltoreq.y.ltoreq.1.0). The rechargeable electrochemical device offers a high discharge voltage, a large discharge capacity, linear discharge voltage, and the capacity to withstand over-charging.

Abstract: Immobilization of enzymes is carried out by covering the surface of a solid support with an enzyme and then contacting the enzyme with an immobilizing reagent in the vapor phase. The immobilizing reagent is preferably an aldehyde or a polymerized aldehyde. By having the immobilizing reagent in vapor phase, the immobilizing reagent concentration can be easily controlled by the vapor pressure. Additionally, there is obtained a uniform covering of immobilized enzyme on the support, and support surfaces which are uneven or curved can be covered with immobilized enzyme regardless of size.

Abstract: The disclosure is directed to an improved enzyme electrode which includes a first electrode having at least one kind of an enzyme immobilized on it for electrochemically detecting a substance to be produced in association with a reaction based on the enzyme, and a second electrode for electrochemically removing materials which interfere with the detection by the first electrode. The second electrode is disposed at the side of a test solution containing a substrate of the enzyme with respect to the first electrode.

Abstract: An immobilized enzyme electrode effective in measurement of the substrate concentration of the enzyme and in conversion from enzyme reaction energies into electric energies. The immobilized enzyme, of an oxidase system, such as glucose oxidase, amino acid oxidase, xanthine oxidase or the like and a metal oxide capable of constituting a redox system which is reduced through coupling with these enzyme reactions and is electrochemically oxidized (anodic oxidation) are combined with each other. The use of the enzyme electrode allows the determination quantity of the enzyme substrate as extremely low as approximately 10.sup.-5 to 10.sup.-6 mole/l in concentration.

Abstract: Improvements in a coenzyme electrode used to electrochemically measure the activity of enzyme or substrate concentration of the enzyme easily. The coenzyme is immobilized, without using a semipermeable membrane, on the electron collector directly with the chemical bond, particularly the covalent bond, whereby the activity of the oxide-reductase requiring the coenzyme can be measured. In addition, the oxide-reductase requiring the coenzyme is also immobilized together with such immobilized coenzyme to improve the characteristics of the conventional enzyme-coenzyme immobilized electrode.

Abstract: Improvements in a coenzyme electrode used to electrochemically measure the activity of enzyme or substrate concentration of the enzyme easily. The coenzyme is immobilized, without using a semipermeable membrane, on the electron collector directly with the chemical bond, particularly the covalent bond, whereby the activity of the oxido-reductase requiring the coenzyme can be measured. In addition, the oxido-reductase requiring the coenzyme is also immobilized together with such immobilized coenzyme to improve the characteristics of the conventional enzyme-coenzyme immobilized electrode.

Abstract: An enzyme electrode, which comprises an oxidoreductase including, where necessary, a coenzyme; a redox polymer acting as an electron mediator in an enzymatic reaction; and an electron collector, wherein the oxidoreductase and the redox polymer are both maintained in the immobilized state on or in the neighborhood of the electron collector by either one of the methods of; entrapping them with a semi-permeable membrane in the neighborhood of the electron collector, or chemically superimposing them on the electron collector or moulding them including the electron collector in a unit with the help of chemical treatment.