Abstract: The present disclosure relates to a sensor and a measuring system and a sensor network that incorporate one or more such sensors. An example sensor could be configured to measure a conductivity of a liquid. The sensor includes a first electrode and a second electrode, each electrode having a surface area, wherein the surface area of the electrodes determines a cell constant of the sensor (Kcell), and wherein at least one of the electrodes is provided with a switching means arranged so that the surface area of the respective electrode can be changed, thereby varying the cell constant (Kcell) of the sensor.

Abstract: Systems and methods described herein include a reference electrode for being immersed in a bulk solution. The reference electrode comprises a reservoir having reservoir walls defining a reservoir volume filled with an electrolyte; an electrode in the reservoir, in contact with the electrolyte. The reservoir of the reference electrode is closed except for the presence of at least one pore in at least one of the reservoir walls, the at least one pore being filled with electrolyte and being adapted for allowing ionic contact between the electrolyte in the reservoir and the bulk solution into which the reference electrode is to be immersed.

Abstract: The present disclosure relates to a sensor and a measuring system and a sensor network that incorporate one or more such sensors. An example sensor could be configured to measure a conductivity of a liquid. The sensor includes a first electrode and a second electrode, each electrode having a surface area, wherein the surface area of the electrodes determines a cell constant of the sensor (Kcell), and wherein at least one of the electrodes is provided with a switching means arranged so that the surface area of the respective electrode can be changed, thereby varying the cell constant (Kcell) of the sensor.

Abstract: A micromachined ion-selective electrode for an ion-selective sensor is provided. The ion-selective electrode includes a reservoir that is arranged to contain electrolyte, a contacting electrode that is arranged at least partially within the reservoir to contact electrolyte in the reservoir, and an ion-selective membrane that is arranged to contact a bulk solution under test. The ion-selective electrode further includes a constriction for providing an ionic connection between the bulk solution and electrolyte in the reservoir via the ion-selective membrane. Also provided is an ion-selective sensor that includes at least one such micromachined ion-selective electrode.

Abstract: An ion sensor for sensing an ion concentration in a bulk solution comprises a reference electrode embedded in an reference electrolyte solution, and a first ion-selective electrode. The ion sensor moreover comprises a second electrode sensitive to the reference ions or to an ion different from the ion to be measured, whereby the second electrode is in direct contact with the bulk solution when the ion sensor is immersed therein. The potential difference between the first electrode and the reference electrode is a measure for the ion concentration in the bulk solution and is corrected with the potential difference between the second electrode and the reference electrode to compensate for the drift of the reference electrode.

Abstract: An electrode for biopotential sensing comprising a main electrode base and at least a plurality of contact pins protruding from the main electrode base and configured to make contact with a subject's skin. Each of the first plurality of contact pins comprises at least one conductive mesh having an elongated pillar shape. A headset or biopotential monitoring system comprising such an electrode for biopotential sensing.

Abstract: Systems and methods described herein include a reference electrode for being immersed in a bulk solution. The reference electrode comprises a reservoir having reservoir walls defining a reservoir volume filled with an electrolyte; an electrode in the reservoir, in contact with the electrolyte. The reservoir of the reference electrode is closed except for the presence of at least one pore in at least one of the reservoir walls, the at least one pore being filled with electrolyte and being adapted for allowing ionic contact between the electrolyte in the reservoir and the bulk solution into which the reference electrode is to be immersed.

Abstract: An ion sensor for sensing an ion concentration in a bulk solution comprises a reference electrode embedded in an reference electrolyte solution, and a first ion-selective electrode. The ion sensor moreover comprises a second electrode sensitive to the reference ions or to an ion different from the ion to be measured, whereby the second electrode is in direct contact with the bulk solution when the ion sensor is immersed therein. The potential difference between the first electrode and the reference electrode is a measure for the ion concentration in the bulk solution and is corrected with the potential difference between the second electrode and the reference electrode to compensate for the drift of the reference electrode.

Abstract: An electrode for biopotential sensing comprising a main electrode base and at least a plurality of contact pins protruding from the main electrode base and configured to make contact with a subject's skin. Each of the first plurality of contact pins comprises at least one conductive mesh having an elongated pillar shape. A headset or biopotential monitoring system comprising such an electrode for biopotential sensing.

Abstract: An electrochemical ethylene sensor and method for ethylene sensing are disclosed. In one aspect, an electrochemical ethylene sensor includes a working electrode and a counter electrode on an electrically insulating substrate. An ionic liquid layer covers the working electrode and counter electrode. In one method, a voltage is applied to the working electrode which is equal to or lower than the voltage required for the onset of oxidation of the material of the working electrode, for example, in the range spanning 700 mV before the onset of oxidation of the material of the working electrode.

Abstract: This application describes methods and apparatus for monitoring of fluid content that are suitable for in-situ, real time and/or continuous monitoring, especially of bodily fluids and in particular the content of sweat. The application also describes fabrication of such an apparatus. The apparatus comprises a multilayer structure comprising at least two electrode layers for detection of fluid content separated by at least one insulating layer. The multilayer structure defines at least one flow channel which provides a flow path for continuous flow of fluid in use, and the electrode layers form part of the sidewall of the flow channel(s). The flow channel(s) may run in a direction substantially perpendicular to the layers. The electrode layers may employ electrochemical detection and may comprise a reference electrode and an ion-sensitive electrode. The apparatus may be fabricated using various printing or deposition techniques.

Abstract: An electrochemical ethylene sensor and method for ethylene sensing are disclosed. In one aspect, an electrochemical ethylene sensor includes a working electrode and a counter electrode on an electrically insulating substrate. An ionic liquid layer covers the working electrode and counter electrode. In one method, a voltage is applied to the working electrode which is equal to or lower than the voltage required for the onset of oxidation of the material of the working electrode, for example, in the range spanning 700 mV before the onset of oxidation of the material of the working electrode.