The monitoring probe (1) comprises: a FR-4 substrate (2) with two faces; two copper tracks (3) arranged on one of the faces of the substrate (2), with an electrical contact terminal (7) on the outside of the probe (1); a conductive region (6) with reference electrode functions, with an electrical contact terminal (8) on the outside of the probe (1), occupying the entire other face of the substrate (2); a passivating material layer (5) partially covering the copper tracks (3) and leaving two free zones (12, 13) of said tracks (3) uncovered, one of said free zones (12) corresponding to the electrical contact terminal (7) of the two copper tracks (3); and two ISE sensor elements (4) that are sensitive to at least one of the parameters of interest to be monitored in the ground, and arranged in the other of the free zones (13) of the two copper tracks (3).

Disclosed are methods and devices for biomolecular detection, comprising a nanopipette, exemplified as a hollow inert, non-biological structure with a conical tip opening of nanoscale dimensions, suitable for holding an electrolyte solution which may contain an analyte such as a protein biomolecule to be detected as it is passed through the tip opening. Biomolecules are detected by specific reaction with peptide ligands chemically immobilized in the vicinity of the tip. Analytes which bind to the ligands cause a detectable change in ionic current. A sensitive detection circuit, using a feedback amplifier circuit, and alternating voltages is further disclosed. Detection of IL-10 at a concentration of 4 ng/ml is also disclosed, as is detection of VEGF.

A portable device for detecting the nutrition level of a plant includes an outer casing and a detection circuit. The outer casing includes belt pulleys, a cam, upper and lower clamping plates. The detection circuit is arranged in the outer casing and realizes an electric signal processing function and a display function. The portable device for detecting the nutrition level of the plant has the following beneficial effects: the device can be used for analyzing whether nutrient elements in crops are deficient or excessive, which is taken as the basis for accurate fertilization, and the device has low detection cost, high real-time capability, small size and is portable.

A calibration electrode for calibrating a reference system of an electrochemical sensor, such as a potentiometric sensor or an ion selective electrode. The calibration electrode has an active surface comprising redox functionalities. The redox functionalities set the pH of a reference solution proximal to the calibration electrode. A voltammetric signal is applied to the calibration electrode to produce a response that is determined by the set pH. The response of the calibration electrode to the voltammetric signal is used to calibrate/adjust a reference potential produced by a reference electrode of the reference system of the electrochemical sensor. This calibration corrects the detrimental effect of reference electrode drift.

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) with a polymeric sensor sleeve (230), which is electrically isolating, disposed within the protective outer shaft.

A gel for use in a pH or an ORP sensor, components of the gel comprising water, a reference electrolyte salt, a buffering system for adjusting pH of the gel, and a polymeric gelling agent, and the gel does not degrade under gamma irradiation.

An electrochemical half-cell includes an electrical terminal lead in contact with a solid electrolyte, wherein the solid electrolyte includes a doped high-entropy oxide. The electrochemical half-cell can be used as either a reference half-cell or a measuring half-cell. Methods of manufacturing the solid electrolyte and the electrochemical half-cell are further disclosed.

A solid state gel for use in a pH sensor comprises a reaction product of water, a buffer system for adjusting pH of the gel when in a liquid state, polyethylene glycol or its derivatives as a gelling agent and a salt wherein the water, the buffer, the polyethylene glycol and a reference electrolyte salt when mixed while in a liquid state form a mixture that was subjected to Gamma irradiation to form the reaction product.

An apparatus, method and sensor for measuring gas concentration. The apparatus includes a sensing unit and a processing unit. The sensing unit includes a first selective water vapour-permeable membrane, a first working electrode and a second working electrode. The first selective water vapour-permeable membrane allows the first working electrode to be in contact with water molecules while to prevent this first working electrode from being in contact with the gas molecules to be measured. The first working electrode generates an electrical signal caused by change in relative humidity, the second working electrode generates a superimposed electrical signal caused by the change in relative humidity and the gas molecules to be measured, and the processing unit acquires concentration of the gas based on the electrical signal and the superimposed electrical signal.

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.