A potentiometric cell capable of selectively measuring potassium comprising an ion-selective electrode composed between 1.5 and 2.4 mg of Valinomycin, between 0.4 and 0.6 mg of potassium Tetrakis (4-chlorophenyl) borate (KTFPB), between 52.48 and 78.72 mg of Poly(vinylchloride) (PVC), and between 103.52 and 155.28 mg of Bis(2-ethylhexyl) sebacate (DOS) dissolved in a carrier solvent such as 1 mL of THF (Tetrahydrofuran) in combination a especially adapted reference electrode. Such a cells exhibit improved precision in potassium ion determinations. Additionally, they exhibit high selectivity for potassium ions over other cations in a sample specimen such as whole blood or saliva. Further, these compositions exhibit these improved properties over a long period of time and therefore have greater shelf life.

A potential measurement device includes a plurality of read-out electrodes arranged in an array shape and that detects a potential at a potential generation point generated due to a chemical change, and a reference electrode that detects a reference potential. The reference electrode is arranged within the array of the read-out electrodes. With this configuration, a low-noise potential measurement device in which noise superimposed on a wire from each of the read-out electrodes to an amplifier and noise superimposed on a wire from the reference electrode to the amplifier, i.e., wiring noise, can be reduced is achieved.

A combination electrode includes a working electrode, a reference electrode, a hydrogel diaphragm, an outer tube and an inner tube. The working electrode is disposed in the inner tube. The reference electrode is disposed in a reference chamber formed between the inner tube and the outer tube. The hydrogel diaphragm seals the opening between an end of the outer tube and the inner tube when the hydrogel swells upon coming in contact with a first electrically conductive fluid that is introduced into the reference chamber. The diaphragm is coupled to the reference electrode in an electrically conductive manner through the first electrically conductive fluid, which contacts both the reference electrode and the diaphragm. The inner tube is closed by a glass membrane that is coupled to the working electrode in an electrically conductive manner through a second electrically conductive fluid that contacts both the glass membrane and the working electrode.

A pH combination electrode includes inner and outer tubes, working and reference electrodes, and a hydrogel diaphragm between the tubes. A seal is disposed inside the inner tube closer to a first inner tube end than to the second inner tube end. An extended reference chamber is formed inside the inner tube between the seal and the second inner tube end. A first conductive fluid is contained in the inner tube between the seal and the first inner tube end. A second conductive fluid is contained in the extended reference chamber and in a reference chamber formed between the inner and outer tubes. A through-hole in the inner tube allows the second conductive fluid to flow between the reference chamber and the extended reference chamber. The working electrode extends into the inner tube, through the seal and into the first conductive fluid. The reference electrode contacts the second conductive fluid.

Provided is an electrical circuit for electrochemical measurement of a solution, said electrical circuit comprising: a voltage generation circuit; an operational amplifier that has an output (OUT), a non-inverting input (+IN), and an inverting input (−IN), wherein the output (OUT) is connected to a counter electrode (CE) in contact with the solution, the inverting input (−IN) is connected to a reference electrode (RE) in contact with the solution, and the non-inverting input (+IN) is connected to the voltage generation circuit; a capacitor that is connected between the output (OUT) and inverting input (−IN) and has a capacitance of 1 μF or greater; and a current measurement circuit that is connected to a working electrode (WE) in contact with the solution.

This disclosure provides techniques for extending useful life of a reference electrode, as well as a novel voltametric system and measurement cell design and related chemistries. An automated, repeatable-use system features a reference electrode that directly immerses a metallic conductor into an analyte, with electrolytes (e.g., chlorides) used for measurement being separately added and removed for each measurement cycles; the metallic conductor can optionally be left exposed to clean dry air in between measurements. In one implementation, the system can be restricted to application with specific analytes (e.g., ground water) that are known in advance to be free of substances that could degrade reference electrode use or lifetime. Cleaning solutions can optionally be used that would not be practical with conventional (insulated) reference electrode designs. In another embodiment, a measurement cell can be configured to receive separated electrode modules, permitting independent cleaning/removal of the working electrode (or other electrodes).

A reference system for an electrochemical or ion selective sensor where a reference electrode is coupled with a redox active species and the redox active species is configured to set a pH value of a local environment of a low buffer/low buffering capacity analyte media proximal to the reference electrode. The pH value of the low buffer/low buffering capacity proximal to the reference electrode may be controlled to a pH value at least one pH unit above or below pH 7. The voltammetric response of the redox active species is used as a reference and/or reference signal for the electrochemical or ion selective sensor.

A biosensor includes a plurality of electrodes including a working electrode, and a detection layer containing an enzyme for exchanging electrons with the working electrode, a crosslinking agent and an electrically conductive polymer and having a contact area with the working electrode defined by a predetermined area.

The present application discloses improved multiple-use sensor arrays for determining the content of various species in samples of biological origin, in particular in the area of point-of-care (POC) testing for blood gases. The multiple-use sensor array is arranged in a measuring chamber, and the sensor array comprises two or more different ion-selective electrodes including a first ion-selective electrode (e.g. an ammonium-selective electrode being part of a urea sensor), wherein the first ion-selective electrode includes a membrane comprising a polymer and (a) a first ionophore (e.g. an ammonium-selective ionophore) and (b) at least one further ionophore (e.g. selected from a calcium-selective ionophore, a potassium-selective ionophore, and a sodium-selective ionophore), and wherein the first ionophore is not present in any ion-selective electrode in the sensor array other than in the first ion-selective electrode.

A reference electrode including a casing through which one face at one side of a liquid junction that leaches an internal liquid is exposed. The casing is provided with an overhang portion that hangs out on the one face side of the liquid junction and prevents separation of the liquid junction from the casing; and an open portion that leaves a space on the one side of the liquid junction open toward a lateral direction along the one face.