Abstract: A handy blood glucose measurement apparatus irradiates the retina of the eye of the subject with light emitted from light-emitting elements having two different wavelengths, with the light of one wavelength serving as reference light and the light of the other wavelength serving as measurement light. The intensity of the reference light and of the measurement light is obtained and the blood glucose value of the subject is found based upon the difference between these two reflected-light intensities. By focusing his or her eye on a symbol or figure displayed on a display panel in the apparatus, the subject is capable of focusing the light emitted by the light-emitting elements on the retina of the eye in reliable fashion.

Abstract: The present invention provides an ion sensitive film (6) comprising a mixed layer containing a redox manifesting substance manifesting redox function and a polymeric compound containing an ion carrier substance. The present invention also provides a method of producing the ion sensitive film (6) and an ion sensor which uses the film (6). The ion sensitive film (6) of the present invention enables the provision of an ion sensor having excellent durability, preservative stability and sensor characteristics.

Abstract: An electrochemical cell is formed by immersing an electrochemical ion sensor and a reference electrode into a solution of interest, the electrochemical ion sensor exhibiting ion selectivity with respect to an ion of interest and having a high electrode resistance. A current which flows through the electrochemical cell is measured while the potential of the electrochemical ion sensor is held to a constant potential with respect to the reference electrode. The current so obtained are proportional to the logarithm value of the concentration of the ion.

Abstract: An ion sensor of the type wherein a specific type of ion in an aqueous solution is measured by potential response. The sensor includes a conductor base, and a reversible redox polymer film formed directly on a surface of said conductor base. An ion carrier film is formed directly on a surface of said redox polymer film. The carrier film contains an ion carrier substance for allowing the specific type of ions to permeate from the aqueous solution to said polymer film.

Abstract: A calibration solution, which is used when measuring the ion concentration of solution under examination such as blood or other body fluids using a pH sensor or the like ion sensor with a solid electrode, is prepared by adding NaCl to a standard buffer solution and thus setting the ionic strength of the solution to be substantially identical with the ionic strength of solution under examination. A sensor calibration method is also disclosed, in which at least two reference calibration solutions having different pH values are prepared, the electromotive force of the sensor in these calibration solutions is measured by immersing the sensor in the solutions, and a calibration formula is produced from the electromotive force for the pH values of the reference calibration solutions. A predetermined amount of bicarbonate buffer solution is added to the calibration solution to maintain a substantially constant ionic strength of the solution, thus permitting simultaneous calibration of an ion sensor and a gas sensor.

Abstract: A biological information measurement apparatus is adapted to measure biological information in an extracorporeal circuration or in a living body by various measurement circuits comprising circuit elements which are not affected by electrical disturbances, and to transmit the results of measurement in the form of a non-electrical signal which is not affected by electrical disturbances. Measured values from measurement sections are gathered at a central processing section separated from the measurement sections. The processing section converts the measured values into output values, compensates the values for temperature and outputs the values to a display unit and recorder.

Abstract: A miniature, solid-state long-life reference electrode in which the amount of outflow of an internal electrolyte containing a halogen ion is reduced includes a conductor on the periphery of which is formed a sintered body consisting of a silver halide and silver oxide, a water-containing gel enveloping the conductor and including a halogen ion electrolyte, and a hollow tubular body closed by a liquid-junction portion comprising a porous ceramic, or by a partitioning wall having an ion permeable portion of a predetermined diffusion coefficient and volume. In another embodiment, the tubular body of the reference electrode is partitioned by a partitioning wall having an ion permeable portion of a predetermined diffusion coefficient and volume.

Abstract: An oxygen sensor includes an electrically conductive substrate directly coated with an electrolytic oxidative polymeric membrane, which contains a porphyrin compound and a metal complex thereof. Also provided is an oxygen sensor capable of being subjected to a temperature calibration and including an oxygen electrode consisting of an electrically conductive substrate directly coated with a porphyrin derivative compound and a metal complex compound thereof, a reference electrode, a gelled polymeric electrolyte in which the oxygen electrode and reference electrode are immersed, and an oxygen-selective permeable membrane coating the gelled polymeric electrolyte. The electrically conductive substrate according to the present invention is formed from a material inactive with oxygen gas, such as indium tin oxide, iridium oxide, nickel or gold.

Abstract: An oxygen sensor includes an electrically conductive substrate directly coated with an electrolytic oxidative polmeric membrane, which contains a porphyrin compound and a metal complex thereof. Also provided is an oxygen sensor capable of being subjected to a temperature calibration and including an oxygen electrode consisting of an electrically conductive substrate directly coated with a porphyrin derivative compound and a metal complex compound thereof, a reference electrode, a gelled polymeric electrolyte in which the oxygen electrode and reference electrode are immersed, and an oxygen-selective permeable membrane coating the gelled polymer electrolyte.

Abstract: Disclosed is a solid-type ion sensor which does not have an internal liquid chamber. The ion sensor has a laminated structure basically includes an electrically conductive substrate, a redox layer having a redox function covering the surface of the electrically conductive substrate, and an ion-selective layer covering the surface of the redox layer. Also provided is an ion sensor of this type having an insulated thermister imbedded so as to contact the redox layer.

Abstract: Disclosed is an ion sensor having an ion-sensitive substrate provided within a tube at a position recessed from an open end of the tube and having an ion carrier membrane, which is selectively permeable to an ion of interest, filling the space between the opening of the tube and the surface of the ion-sensitive substrate on the open-end side of the tube. A method of manufacturing the ion sensor includes steps of inserting and retaining the ion-sensitive substrate in the tube, filling the space between the ion-sensitive substrate and the tube with a sol-like ion carrier membrane composition, and gelling the sol-like ion carrier membrane composition.

Abstract: A pH sensor includes a substrate formed of an electrically conductive carbon material. A hydrogen ion-sensitive layer is formed on the substrate surface. The layer is formed of an electrooxidation polymer of a nitrogen-containing aromatic compound selected from the group consisting of 1-aminopyrene and a mixture of 1-aminopyrene and pyridine.

Abstract: A pH measurement device includes working and reference electrodes. The working electrode has a linear electrically conductive substrate, at least a distal end surface of which consists of platinum, and a selective hydrogen ion permeable layer formed on the distal end face of the substrate. The reference electrode includes an electric conductor formed to be insulated from the working electrode and surrounding the working electrode, a polymer-silver (I) complex layer formed on the outer circumferential surface of the conductor, and an ion-conductive layer containing an anionic compound and formed on the complex layer. The pH of a solution is measured in accordance with a difference between a potential of the working electrode and that of the reference electrode.

Abstract: A selectively permeable film directly applied to coat the surface of an electroconductive element, said electively permeable film comprising a polymer which is derived from at least one aromatic compound selected from the group of nitrogen-containing aromatic compounds or from the group of hydroxy aromatic compounds. The nitrogen-containing aromatic compounds are aniline, 2-aminobenzotrifluoride, 2-aminopyridine, 2,3-diaminopyridine, 4,4'-diaminodiphenyl ether, 4,4'-methylenedianiline, tyramine, N-(o-hydroxybenzyl)-aniline and pyrrole. The film coated on the electrode surfaces permits selective passage of ions and the electrode can be used as an ions sensor for measuring the concentration of ions in solutions.

Abstract: A reference electrode is prepared by coating the surface of a conductive substrate with a silver complex polymer compound, which is either a compound prepared by the complex formation between a polymer compound containing a coordination nitrogen atom and a silver ion or an aforementioned complex compound containing a silver halide. This reference electrode can be used by a combination with ion sensor, a pH sensor and so on.