The present disclosure relates to a potentiometric probe for measuring a measured variable that represents an ion concentration in a measuring medium, including a probe base including a sensor circuit, and two electrochemical half-cells arranged such that one of the half-cells surrounds at least one portion of the other half-cell, wherein at least one of the half-cells is configured as a module which is connected to the probe base via a mechanical and electrical interface. In another embodiment, one of the half-cells is a measuring half-cell including an ion-selective membrane and a terminal lead which electrically contacts the ion-selective membrane. The other half-cell is a reference half-cell, wherein the measuring half-cell and/or the reference half-cell are each configured as a module which is connected to the probe base via a mechanical and electrical interface.

The invention relates to the field of soil analysis, in particular the technical analysis of agricultural or horticultural soils. In particular, the invention relates to a sensor device for in situ soil analysis, to a method for in situ soil analysis, and to a device set up for carrying out the soil analysis method, wherein said device, together and in interaction with one or more of said sensor devices, represents a system for in situ soil analysis. The sensor device has a sensor assembly comprising one or more sensors which are configured individually or cumulatively for the simultaneous in situ measurement of at least two of the following soil properties of a soil to be analyzed and for providing corresponding respective measurement data: (a) impedance spectrum, (b) temperature, (c) absorption spectrum NIR-VIS-UV in a spectral range from NIR (near infrared spectral range) to UV (ultraviolet spectral range), and (d) acidic or basic character, in particular pH value. In this case, the distance between in each case two of the sensors of the sensor assembly, which is defined with respect to the respective measurement variable sensors, does not exceed a value of 10 cm.

A sensing electrode includes a first electrode assembly, a second electrode assembly and a sealing component. The first electrode assembly includes an inner tubular body and a reference electrode component installed in the inner tubular body. The second electrode assembly includes an outer tubular body and a working electrode component installed in the outer tubular body. The first electrode assembly is installed in the outer tubular body. The sealing component is located between the inner and outer tubular bodies and provided to inhibit infiltration of an etching solution into the outer tubular body and leakage of an electrolyte from the inner tubular body. Thus, the sensing electrode has a better stability and service life.

Apparatus and methods are provided for measuring phosphate in water. The methods can involve electrically pre-treating a potentiometric sensor and using the electrically pre-treated potentiometric sensor in a water sample to obtain a phosphate measurement. The potentiometric sensor includes a working electrode and a counter electrode. The working electrode includes a metal/metal oxide electrode having a detection surface. The electrical pre-treatment generates a metal phosphate on the detection surface of the metal/metal oxide electrode. The phosphate measurement results in a fresh layer of mixed oxide on the detection surface of the metal/metal oxide electrode. The electrically pre-treatment can be performed in situ in the water sample, allowing for field monitoring of water bodies. In some embodiments, the method can also involve cleaning the sensor prior to electrically pre-treating the sensor or after obtaining the phosphate measurement.

A microbial sensor, system, and method that can be used to determine a chemical environment and/or substrate concentrations in anaerobic or aerobic environments, such as soils, sediments and ground waters, are disclosed. An exemplary system uses one or more (e.g., inert) measurement electrodes and a reference electrode. The reference electrode can include an electrode exposed to atmospheric oxygen (e.g., a cathode) or an electrode exposed to stable anaerobic or aerobic conditions. The exemplary microbial sensor system measures open-circuit voltage to characterize the chemical (oxidizing or reducing) environment and/or recovery voltage to measure substrate concentrations in the subsurface.

Various examples are provided related to electrochemical phosphate/pH (P/pH) sensors, systems and related methods. In one example, a P/pH sensor includes a substrate and collocated phosphate (P) electrode and pH electrode formed on a surface of the substrate. The P electrode includes a cobalt (Co) sensing window disposed on a first copper (Cu) sensor pad; and the pH electrode includes an antimony (Sb) sensing window disposed on a second Cu sensor pad. The P/pH sensor can include a reference electrode, and may also include other sensor electrodes such as, e.g., a nitrate electrode.

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-.

There is provided an electrochemical sensor, comprising: a working electrode; a counter electrode; and a base material supporting the working electrode and the counter electrode, wherein the working electrode is a chip-shaped electrode including a diamond film that causes a redox reaction on its surface when a predetermined voltage is applied in a state where a test sample exists between the working electrode and the counter electrode, and a support that comprises a material other than diamond and supports the diamond film, and the working electrode is mounted on the base material, with the support positioned on the base material side and at least a part of a side surface of the support exposed.

An electrochemical sensor for potentiometric measurements in a measurement medium has a sensor head (201) at an end of a longitudinal sensor body (203). A sensing electrode (210) and a reference electrode (220) are disposed within the longitudinal sensor body. A liquid junction (223) is established between the reference electrode and the sensing electrode. The sensor is characterized by a protective outer shaft (250) into which a polymeric tube-like structure (230) is disposed, electrically isolating the protective outer shaft from a reference electrolyte.

An analyte sensor system including a substrate, a first electrode disposed on a first surface of the substrate, a second electrode disposed on a second surface of the substrate, a third electrode provided in electrical contact with at least one of the first or second electrodes, where at least a portion of the first electrode and the second electrode are subcutaneously positioned in a patient, and where the third electrode is substantially entirely positioned external to the patient, and corresponding methods are provided.