A reference electrode according to the present invention maintains continuity between an internal solution and measurement sample and measures the electrical potential of the measurement sample even if the measurement sample in a liquid junction of the reference electrode has air bubbles mixed therein. This reference electrode is provided with: a second body provided with a second internal solution chamber in which a second internal solution is housed and a liquid junction portion disposed in the second internal solution chamber such that the second internal solution and measurement sample that is to be measured come into contact; and an internal electrode disposed inside the second internal solution. The liquid junction portion is formed from a conduction component formed from a porous or fibrous component and an aperture adjacent to the conduction component.

A reference electrode system for a pH-sensor system includes: a first junction having a membrane with a sealed side; a reference electrode, the reference electrode and/or an electrically conducting wire of the reference electrode being covered completely except for an end portion of the reference electrode, by a sleeve; and a tube that is arranged, at least partly, around the reference electrode, the electrically conducting wire, and the sleeve, the tube having a closed end which is arranged near the end portion of the reference electrode.

An example device includes a processor to connect to an electrode disposed within a microfluidic volume and to connect a second electrode that includes a surface of silver metal disposed within the microfluidic volume. The processor is to apply an electrical potential between the electrode and the second electrode when the microfluidic volume contains a fluid that contains chloride ions to form a layer of silver chloride on the surface of the second electrode. The processor is further to cease application of the electrical potential and operate the second electrode as a reference electrode in a measurement process performed within the microfluidic volume.

A sensor element includes: a first inner space into which a measurement gas is introduced from outside; a second inner space communicated with the first inner space; a main pump cell constituted by an inner pump electrode facing the first inner space, an external pump electrode on a surface of the sensor element, and a solid electrolyte located therebetween; a measurement electrode facing the second inner space and functioning as a reduction catalyst for NOx; and a measurement pump cell constituted by the measurement electrode, the external pump electrode, and a solid electrolyte located therebetween. The inner pump electrode is a cermet made of an AuPt alloy containing Au ranging from 0.6 wt % to 1.4 wt % and ZrO.sub.2, and has a thickness ranging from 5 m to 30 m, a porosity ranging from 5% to 40%, and an area ranging from 5 mm.sup.2 to 20 mm.sup.2.

The present disclosure relates to a sensor element for a potentiometric sensor, comprising a substrate formed from a metal alloy and an ion-selective enamel layer arranged on the substrate, wherein the metal alloy comprises at least one transition metal and wherein the ion-selective enamel layer contains a proportion of an oxide of the transition metal, and wherein an electrically conductive transition zone is arranged between the substrate and the enamel layer and contains the transition metal in a plurality of different oxidation states.

A silver-silver chloride electrode contains silicone rubber as a binder in which silver powder, silver chloride powder and silica powder are dispersed. A current density of a current flowing through an electric circuit is equal to or greater than 0.64 A/mm.sup.2 after 5 minutes from the beginning of voltage application to the electric circuit when the electric circuit in which two silver-silver chloride electrodes and a phosphate buffered saline are connected in series is made up of the two silver-silver chloride electrodes and the phosphate buffered saline containing no calcium and no magnesium interposed between the two silver-silver chloride electrodes.

A method for producing a silver-silver chloride electrode includes: producing a paste by mixing silver powder, silver chloride powder, a dispersant, and fumed silica powder with a liquid silicone rubber binder; coating the paste on a substrate made of silicone rubber; curing the paste on the substrate to form an electrode containing silver and silver chloride; and immersing the electrode in a sodium chloride aqueous solution.

A urine testing strip and a urine testing system are provided. The urine testing system includes the urine test strip and a detection device. The urine test strip includes a working electrode, a counter electrode, a reference electrode, a trigger circuit and a protection layer. The protection layer covers the working electrode, the counter electrode and the reference electrode, and portions of the working electrode, the counter electrode and the reference electrode are exposed through an opening of the protection layer. The detection device includes a test strip receiving module and a wireless transmission module. The test strip receiving module is used to receive the test strip and to provide electric power to the test strip for obtaining a detection result. The wireless transmission module is used to transmit the detection result to a mobile computer device.

A sensor element includes: a main pump cell constituted by an inner pump electrode facing the first inner space into which a measurement gas is introduced, an external pump electrode provided on an element surface, and a solid electrolyte located therebetween; a measurement electrode facing a second inner space communicating with the first inner space and functioning as a reduction catalyst for NOx; and a measurement pump cell constituted by the measurement electrode, the external pump electrode, and a solid electrolyte located therebetween. A diffusion resistance from the gas inlet to the inner pump electrode ranges from 200-1000 cm.sup.1, a resistance of the main pump cell is equal to or smaller than 150, a distance between the electrodes ranges from 0.1-0.6 mm, and the inner pump electrode which is a cermet made of an AuPt alloy and ZrO.sub.2 has an area ranging from 5-20 mm.sup.2.

An apparatus to evaluate a stability of a luminescent material includes an electrochemical cell that includes a sample including a solvent and the luminescent material mixed in the solvent, a voltage application device that applies a constant voltage to the sample, a light source that irradiates a source light to the sample, and a photoluminescence measuring device that measures a luminescence spectrum of an emission light generated by the luminescent material.