A fluid analyzer for analyzing fluid samples comprising one or more analytes and a method of calibrating such. The fluid analyzer includes a control system to control at least one automated valve to pass at least three calibration reagents through a fluid channel to a secondary ion selective electrode, a primary ion selective electrode, and a reference electrode, and determine calibration information using calibration logic from signals generated by a meter, control the at least one automated valve to selectively pass different subsets of the at least three calibration reagents through the fluid channel to the secondary ion selective electrode, the primary ion selective electrode, and the reference electrode, and determine re-calibration information using the signals generated by the meter and at least one of the calibration information and re-calibration logic.

A reference electrode with a liquid-impermeable enclosure comprises a chamber for a reference electrolyte. The reference electrode also comprises a first electrode element comprises a reference electrolyte electrode surface arranged to contact a reference electrolyte located within the chamber and a second electrode element is provided at least partially outside the enclosure and comprises a sample electrode surface for contacting a sample. The first and second electrode are electrically connected through the enclosure. Alternatively or additionally, a conductive connecting element defining a part of the enclosure and/or extending through the enclosure electrically connects the first electrode element and the second electrode element.

An embodiment provides a method for measuring an analyte of a sample, including: introducing a sample to a sample region of a measurement device; the measurement device comprising: a measurement electrode and a ground electrode contacting the sample; a low-slope reference electrode in a reference electrode assembly having an electrolyte solution, wherein the electrolyte solution is in contact with the low-slope reference electrode; wherein the electrolyte solution is electrically coupled to the sample via at least one junction; and measuring a first potential between the measurement electrode and the ground electrode; measuring a second potential between the low-slope reference electrode and the ground electrode; determining an analyte in the sample by comparing the first potential and the second potential. Other aspects are described and claimed.

An electrochemical measurement cartridge includes a container including a first analysis chamber for receiving a fluid to be analyzed and a second calibration chamber for receiving a calibration fluid; an electrochemical measurement sensor including at least one work electrode and one reference electrode; a container supporting the sensor and a cover arranged mobile relative to one another to confer on the cartridge at least two separate operating configurations, a first configuration in which the sensor is communicating with the first analysis chamber and a second configuration in which the sensor is communicating with the second calibration chamber; sealing between the chambers of the container and the cover; and a drive member for providing a relative movement of the container relative to the cover.

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 method for producing a polymer membrane for the potentiometric detection of an analyte, the method comprising the following successive steps: providing a formulation comprising a dissolved polymer, an ion exchanger, an ionophore, optionally a plasticiser, and a solvent selected from glycol ethers and acetates thereof, and glycol diacetates, depositing the formulation on a support, for example a transducer, and evaporating the solvent, so as to form a polymer membrane.

The invention provides a solid state reference electrode comprising a reference element embedded in an electrochemically active composite, the electrochemically active composite comprising a polymeric matrix loaded with a solid inorganic salt, wherein the polymeric matrix comprises a cross-linked vinyl polymer of a vinyl monomer containing a heteroatom.

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.

Various apparatus, systems, and methods for measuring a solution characteristic of a sample comprising microorganisms are disclosed. In one embodiment, a sensor apparatus is disclosed comprising a sample container comprising a sample chamber configured to receive the sample and a reference sensor component comprising a reference conduit having a reference conduit cavity defined therein. The reference conduit cavity can be at least partially filled with a reference buffer gel, buffer solution, or wicking component. A segment of the reference conduit can extend into the sample chamber. A reference electrode material can be positioned at a proximal end of the wicking component or extend partially into the reference conduit cavity. The sensor apparatus can also comprise an active sensor component having an active electrode in fluid contact with the sample. The sample in the sample chamber can be aerated through an aeration port defined along a surface of the sample container.

An electrowetting-on-dielectric (EWOD) microfluidic device comprises at least one integrated electrochemical sensor, the electrochemical sensor comprising: a reference electrode; a sensing electrode; and an analyte-selective layer positioned over the sensing electrode. In some embodiments, the electrochemical sensor measures a concentration of an analyte in a fluid sample exposed to the electrochemical sensor based on a potential difference between the reference electrode and the sensing electrode. The first analyte and the second analyte can be selected from a group consisting of K.sup.+, Na.sup.+, Ca.sup.2+, Cl.sup.−, HCO.sub.3.sup.−, Mg.sup.2+, H.sup.+, Ba.sup.2+, Pb.sup.2+, Cu.sup.2+, I.sup.−, NH4.sup.+, (SO4).sup.2−.