Abstract: A method and device for the quantitative determination of an ion in a fluid which comprises subjecting the fluid to voltammetry using a sensing electrode which comprises an electrically conducting support having a surface which is coated with a support matrix, the support matrix containing an electroactive species capable of being oxidised or reduced to form a charged species, and an ionophore.

Abstract: An ion-sensitive sensor arrangement includes: a semiconductor chip having a first surface, which has a media-sensitive region and at least one, first, electrical contact surface; and a support having a second surface, which faces the first surface of the semiconductor chip. An opening is provided, which aligns with the sensitive region, and at least one, second, electrical contact surface, which overlaps, or aligns with, the at least one, first, electrical contact surface. Between the support and the semiconductor chip, a preferably elastic, anisotropic conductor is arranged, which produces a conducting connection between the at least one, first, contact surface and the at least one, second, contact surface, and which has a traversing opening, which aligns with the opening, so that the sensitive region of the semiconductor chip can be contacted through the opening by an analyte. The preferably elastic, anisotropic conductor seals the region outside of the opening against contamination with the analyte.

Abstract: The invention relates to an embedded bodily fluid analysis device comprising a measuring cell containing the bodily fluid to be analyzed, at least one reference cell containing a reference standard and an electronic measuring circuit. The measuring cell is provided with at least one work electrode of the measuring cell and with at least one reference electrode of the measuring cell. The reference cell is provided with at least one work electrode of the reference cell formed by the same material or materials as a work electrode of the measuring cell and with at least one reference electrode of the reference cell formed by the same material or materials as a reference electrode of the measuring cell.

Abstract: The invention defines an all-solid-contact ISE which comprises a transducer layer of carbon nanotubes which brings the sensing layer and conducting element into contact. The invention also defines a method for the preparation of said all-solid-contact ISE and the use of the same for the qualitative, quantitative or semi-quantitative analysis of analytes. Said all-solid-contact ISE makes it possible to detect or quantify highly diverse chemical species in a reliable and reproducible manner, with the added advantages derived from its simplicity and low construction cost.

Abstract: The present invention relates to planar electrochemical sensors with membrane coatings used to perform chemical analyses. The object of this invention is to provide unit-use disposable sensors of very simple and inexpensive construction, preferably with only a single membrane coating on an electrode. The invented devices are potentiometric salt-bridge reference electrodes and dissolved gas sensors constructed with a heterogeneous membrane coating of a conductor. The heterogeneous membrane, which is an intimate admixture of a hydrophobic and a hydrophilic compartment, concurrently supports constrained transport of non-volatile species through its hydrophilic compartment and rapid gas and water vapor transport through its hydrophobic compartment.

Abstract: A system automatically maintains at least one of a pH level and a sanitizing agent level of water in a water feature. The system includes a sensor assembly responsive to at least one of a pH level of the water and a sanitizing agent level of the water. The system further includes a controller which generates control signals in response to signals from the sensor assembly. The system further includes at least one of a first source containing a sanitizing agent material and a second source containing a pH-modifying material. The system further includes a third source comprising a valve assembly and a third container containing a liquid calibrant material. The valve assembly is responsive to at least a portion of the control signals from the controller by selectively allowing the calibrant material to flow from the third container through the sensor assembly to the water feature.

Abstract: Methods and devices for point of care determination of heparin concentration in blood are described. Cartridges including protamine ion sensitive electrodes (ISEs) and reference electrodes and systems for automatically determining heparin concentration in the cartridges are provided. Some systems add blood to a protamine bolus sufficient to bind all heparin, leaving excess protamine. The excess protamine concentration can be determined by measuring the initial slope of the electrode potential rate of change, and comparing the slope to known protamine concentration slope values In some cartridges, an oscillating pressure source moves the blood-protamine mixture back and forth across the protamine ISE. Some systems also use a second blood sample having the heparin removed or degraded to create a blank reference sample. Protamine ISEs can include polyurethane polymer, DNNS ionophore, and NPOE plasticizer.

Abstract: An electrochemical sensor for measuring the amount of hydrogen sulphide or thiols in a fluid in a wellbore comprises a temperature- and pressure-resistant housing containing a flow path for the fluids. The fluids flow over one side of a gas permeable membrane made of zeolite or a suitable ceramic material, the other side of the membrane being exposed to a chamber containing a reaction solution which together with the hydrogen sulphide or thiols create a redox reaction resulting in an electrical current dependent upon the amount of hydrogen sulphide or thiols in the fluid.

Abstract: In this invention, a separative structure of the ion-selecting electrode is applied to fabricate the dual type potentiometric biosensor for creatinine detection. According to the fabrication process, the creatinine enzyme is immobilized onto a conductive layer of a substrate of pH sensing membrane and ammonium ion-selecting membrane. The conductive layer provides with a sensing region and a non-sensing region. A conductive line is extended from the conductive layer for using as an external electrical contact point. The dual type potentiometric creatinine biosensor was fabricated by using the enzyme immobilization method onto the surface of the selecting membrane of sensing membrane of pH sensing electrode and creatinine sensor.

Abstract: Provided is a rotatable disc-shaped microfluidic device which can electrochemically detect electrolytes comprised in a specimen. The microfluidic device including: a specimen chamber which accommodates a specimen; a detection chamber which receives the specimen from the specimen chamber; and an ion sensor which is formed in the detection chamber to electrochemically detect electrolytes in the specimen and includes an indicator electrode, a standard electrode and an ion selective film formed on a portion of the indicator electrode. The standard specimen is accommodated in the detection chamber, and a standard potential is measured. Then, the specimen is accommodated in the detection chamber, and a measurement potential is obtained to detect the concentration of the electrolytes comprised in the specimen.

Abstract: A biosensor containing ruthenium, measurement using the same, and the application thereof. The biosensor comprises an extended gate field effect transistor (EGFET) structure, including a metal oxide semiconductor field effect transistor (MOSFET), a sensing unit comprising a substrate, a layer comprising ruthenium on the substrate, and a metal wire connecting the MOSFET and the sensing unit.

Abstract: The invention is directed to conductive polymer compositions, catalytic ink compositions (e.g., for use in screen-printing), electrodes produced by deposition of an ink composition, as well as methods of making, and methods of using such compositions and electrodes. An exemplary ink material comprises a metal catalyst (e.g., platinum black and/or platinum-on-carbon), graphite as a conducting material, a polymer binding material, and an organic solvent. In one aspect, the polymer binding material comprises a polymer binder blend comprising first and second polymers, wherein the first polymer has a glass transition temperature higher than the second polymer. In a second aspect, the polymer binding material comprises a hydrophilic acrylic polymer, copolymer, or terpolymer. The conductive polymer compositions of the present invention may be used, for example, to make electrochemical sensors. Such sensors may be used, for example, in a variety of devices to monitor analyte amount or concentrations in subjects.

Abstract: A sensor for monitoring concentration of a constituent in a gas may include an ionically conductive layer and a sensing electrode coupled to the ionically conductive layer. The sensing electrode may be exposed to a gas. The sensor may also include a reference electrode that is exposed to the gas and made of substantially a same material as the sensing electrode.

Abstract: An electrochemical suspended element-based sensor system includes a solution cell for holding an electrolyte comprising solution including at least one electrochemically reducible or oxidizable species. A working electrode (WE), reference electrode (RE) and a counter electrode (CE) are disposed in the solution. The CE includes an asymmetric suspended element, wherein one side of the suspended element includes a metal or a highly doped semiconductor surface. The suspended element bends when current associated with reduction or oxidation of the electrochemically reducible or oxidizable species at the WE passes through the suspended element. At least one measurement system measures the bending of the suspended element or a parameter which is a function of the bending.

Abstract: A potentiometric sensor, especially a pH-sensor or redox-sensor, includes: an elementary sensor for registering a potentiometric parameter, especially a pH-value or a redox potential; and an interface for issuing a potentiometric-parameter-dependent signal to a superordinated unit, especially a transmitter; wherein the potentiometric sensor of the invention has a digital data memory, which is permanently connected with elementary sensor.

Abstract: The present application relates to a pressurized reference electrode and to a process for its production, said reference electrode comprising a chamber (11) which has a flowable reference electrolyte, and a portion of the wall of said chamber being formed from porous material (10) for contacting said reference electrode with a measuring medium, and said chamber being under overpressure, which is characterized in that the overpressure is generated in said reference electrode by introducing a gas or/and a liquid through said porous material of the wall in said chamber, or introducing said reference electrolyte into said chamber and closing said chamber under pressure.

Abstract: Methods and devices for point of care determination of heparin concentration in blood are described. Cartridges including protamine ion sensitive electrodes (ISEs) and reference electrodes and systems for automatically determining heparin concentration in the cartridges are provided. Some systems add blood to a protamine bolus sufficient to bind all heparin, leaving excess protamine. The excess protamine concentration can be determined by measuring the initial slope of the electrode potential rate of change, and comparing the slope to known protamine concentration slope values In some cartridges, an oscillating pressure source moves the blood-protamine mixture back and forth across the protamine ISE. Some systems also use a second blood sample having the heparin removed or degraded to create a blank reference sample. Protamine ISEs can include polyurethane polymer, DNNS ionophore, and NPOE plasticizer.

Abstract: An electrochemical electrode probe includes an elongated body of a porous material disposed in a housing. The porous material is permeated with an electrolyte. A body of electrode material surrounds the porous body and functions as one electrode of an electrochemical system. A portion of the elongated body of porous material projects beyond the electrode body and functions to establish ionic and electrical conductivity with a sample of material which is to be tested. The sample of material functions as a working electrode, and the electrode body of the probe functions as a counter electrode/reference electrode. Further disclosed is an electrochemical analysis system which includes the probe and a support plate operable to retain a plurality of samples of test material thereupon. The probe is moved across the plate to sequentially measure the electrochemical properties of the various samples of material. Also disclosed are methods for using the system.

Abstract: A sensing apparatus comprising an ion sensitive field effect transistor arranged to generate an electrical output signal in response to localized fluctuations of ionic charge at or adjacent the surface of the transistor, and means for detecting the electrical output signal from the ion sensitive field effect transistor, the localized fluctuations of ionic charge indicating events occurring during a chemical reaction.

Abstract: Nanopore based ion-selective electrodes and methods of their manufacture as well as methods for their use are disclosed and described. The nanopore based ion-selective electrode can include a pore being present in a solid material and having a nanosize opening in the solid material, a metal conductor disposed inside the pore opposite the opening in the solid material, a reference electrode material contacting said metal conductor and disposed inside the pore, a conductive composition in contact with the reference electrode and disposed in the pore, and an ion-selective membrane. The ion-selective membrane can be configured to isolate the metal conductor, reference electrode material, and conductive composition together within the pore.

Abstract: Methods and systems for simultaneously measuring concentration of two or more different cations in solution. The methods include the steps of applying a steady state polarization technique to a solution comprising two or more different cations; measuring the limiting currents of the solution; and correlating the limiting currents with the concentration of the different cations. The system includes a working electrode; a potentiostat; a counter electrode; a reference electrode; a solution comprising different cations to be analyzed; and a model for correlating the limiting currents with the concentration of the pair cations. The working electrode may be any electrode compatible with the media, including noble metals, carbon, or combinations thereof. In some embodiments, the working electrode is a rotating disk electrode (RDE).

Abstract: A reference electrode including a water-impermeable, non-conductive substrate having a surface; an electrically conductive metal/metal salt mixture layer in contact with the surface; a water-soluble alkali metal salt layer; and a water-impermeable barrier layer overlaying a portion of the alkali metal salt layer and a portion of the metal/metal salt layer, and a method for preparing same are described. When the reference electrode is placed in a water sample to be tested, water enters the exposed portion of the alkali metal salt layer where it dissolves the salt forming a saturated solution in the region of contact between the alkali metal salt layer and the metal/metal salt layer.

Abstract: The present invention relates to a test tool (X1) attached to an analyzing device (1) for analyzing a sample. The test tool (X1) includes a pinching portion (6) for attachment to the analyzing device (1) or removal from the analyzing device (1). The pinching portion (6) may include recesses or projections.

Abstract: A sensor card for determining analytes in liquid and gas samples with films connected to one another in sheetlike fashion, namely a sensor film facing the sample with openings and a covering film remote from the sample with openings for electrical tapping, at least one sensor being provided and arranged between the sensor film and the covering film. There is provided between the sensor film and the covering film at least one intermediate film, in which cutouts are provided, the sensor being arranged in one of the cutouts. The sensor card provides a homogeneous thickness, which brings about a reliable sealing of the flow channels for the liquid sample if the sensor card is connected to a plate that partially forms the flow channels within the analysis system. Furthermore, the invention relates to a method for producing such a sensor card.

Abstract: A test meter system includes a cartridge that houses a test strip tape, which includes a plurality of test elements, and the cartridge defines a meter opening. The cartridge further incorporates an indexing mechanism for indexing the test strip tape. A meter is configured to analyze body fluid via the test strip tape, and the meter includes a display for displaying test results as well as other information. At least a portion of the meter is received in the meter opening of the cartridge to provide a compact configuration. In one form, the test strip system has a generally cylindrical outer shape to provide a pleasing handheld shape.

Abstract: The present claimed invention is to provide a reference electrode wherein variations of a potential difference at a liquid junction can be removed almost completely, contamination of a sample solution can be minimized, a frequency to supply and replace an internal solution is lessened, the liquid junction is prevented from being clogged, high durability for a long term can be maintained and a measurement with high accuracy can be conducted, and comprises an internal electrode 21, an internal solution 22 that makes a contact with the internal electrode 21 and a liquid junction 23 that continues into the internal solution 22, wherein the liquid junction 23 is made by the use of a gelled hydrophobic ionic liquid.

Abstract: A method, an electrode, a measuring cell, and a measuring device are disclosed which can detect and quantitatively determine an analyte having specific bonding properties, in a highly sensitive, simple and accurate manner using photocurrent. This method comprises contacting a working electrode and a counter electrode with an electrolyte medium, wherein the working electrode has an analyte immobilized thereon through a probe substance and wherein the analyte is bonded to a sensitizing dye; irradiating the working electrode with light to photoexcite the sensitizing dye; and detecting photocurrent flowing between the working electrode and the counter electrode, wherein the photocurrent is generated by transfer of electrons from the photoexcited sensitizing dye to the working electrode.

Abstract: A wireless chemical sensor includes an electrical conductor and a dielectric material on the conductor. The conductor is electrically unconnected and is shaped for storage of an electric field and a magnetic field. In the presence of a time-varying magnetic field, the conductor resonates to generate harmonic electric and magnetic field responses, each of which has a frequency associated therewith. The dielectric material is selected such that it experiences changes in dielectric attributes thereof in the presence of a chemical-of-interest. Shifts from the sensor's baseline frequency response indicate that the dielectric material has been exposed to the chemical-of-interest.

Abstract: The present invention is an electrochemical cell system gas sensor that detects a subject substance to be detected using an electrochemical reaction system and comprises an ion conduction phase and at least two kinds of electrode facing each other and contacting the ion conduction phase, an electrode structure thereof comprising a chemical detection electrode layer having a selective adsorption characteristic relative to the subject substance to be detected and at least one reference electrode layer serving as a counter electrode to the chemical detection electrode layer, a manufacturing method thereof, and a method of detecting the subject substance to be detected, the present invention provides a chemical detection system having an extremely high response speed and great detection ability irrespective of high or low temperatures and even in the presence of excessive oxygen that impairs the chemical reaction of the subject substance to be detected.

Abstract: A potentiometric sensor for measuring a potentiometric variable of a medium comprises an ISFET whose gate region exhibits an ion-sensitive surface which can be exposed to the medium and which outputs an output signal that depends on the concentration of the ions at the ion-sensitive surface of the gate region. An evaluation circuit with a measuring input to which the output signal of the ISFET is applied is included, whereby the evaluation circuit is designed to output a measured value for the potentiometric variable, depending on the output signal. Also included is a measuring resistor which is arranged between the output of the ISFET and the input of the evaluation circuit, a monitoring circuit to determine the voltage drop over the measuring resistor, and a bridge section that is parallel to the measuring resistor to bridge the measuring resistor whereby the bridge section exhibits a switch with which the bridge section can be opened or closed.

Abstract: A calcium ion sensor is provided. The calcium ion sensor includes a metal oxide semiconductor field effect transistor, a sensing unit including a substrate, a ruthenium dioxide membrane formed thereon and a calcium ion sensing membrane formed on the ruthenium dioxide membrane, and a conductive wire connecting the metal oxide semiconductor field effect transistor and the sensing unit. The invention also provides a method for fabricating a calcium ion sensor, and a sensing system including the sensor.

Abstract: Method for microanalyzing ions with the following steps: placing a volume of an ionic liquid (2) inside a cavity (1) having an internal volume, where the volume of said liquid is smaller than said internal volume; placing inside said internal cavity (1) a solution (4) containing said ions (C+, A?) to be analyzed, where the solvent of the solution (4) and the ionic liquid (2) are chosen for being immiscible and allowing an ion transfer (C+, A?) from said solution (4) to said ionic liquid (2); and detecting the presence of said ions (C+, A?) in said ionic liquid (2) using an analysis means (3) for analysing at least one type of ion in solution in said ionic liquid (2), in a free state or in a complex, said analysis means (3) being contacted with said ionic liquid (2). A device and a system for carrying out this method are also provided.

Abstract: Apparatus and method for detecting current or potential generated in a liquid sample suitable for use in a chromatography or other liquid sample analytical system. One embodiment is an electrolytic ion transfer device with a signal detector in communication with the electrodes of the transfer device. Another is a combination ion transfer device/electrolyte generator. Another substitutes a detector for the ion transfer device in the combination.

Abstract: An electro-active sensor includes a nonconductive platform with a first electrode set attached with a first side of a nonconductive platform. The first electrode set serves as an electrochemical cell that may be utilized to detect electro-active species in solution. A plurality of electrode sets and a variety of additional electrochemical cells and sensors may be attached with the nonconductive platform. The present invention also includes a method for constructing the aforementioned electro-active sensor. Additionally, an apparatus for detection and observation is disclosed, where the apparatus includes a sealable chamber for insertion of a portion of an electro-active sensor. The apparatus allows for monitoring and detection activities. Allowing for control of attached cells and sensors, a dual-mode circuitry is also disclosed. The dual-mode circuitry includes a switch, allowing the circuitry to be switched from a potentiostat to a galvanostat mode.

Abstract: A test strip for measuring a signal of interest in a biological fluid when the test strip is mated to an appropriate test meter, wherein the test strip and the test meter include structures to verify the integrity of the test strip traces, to measure the parasitic resistance of the test strip traces, and to provide compensation in the voltage applied to the test strip to account for parasitic resistive losses in the test strip traces. In addition, conductive traces are positioned to ensure structural interrogation of all electrodes and traces present upon the test strip.

Abstract: The invention provides a reference electrode including a liquid electrolyte containing water, a water soluble organic compound with molecular size and boiling point are both greater than water, and an ionic salt; a solid crystal of the ionic salt in the liquid electrolyte; a metal/metal salt complex layer in contact with the liquid electrolyte; an leading wire connected to the metal/metal salt complex layer; an insulation case for containing the liquid electrolyte; and a nano-porous junction material embedded in the insulation case for contacting the liquid electrolyte, wherein a pore size of the nano-porous junction material is greater than a cation diameter of the ionic salt but smaller than a molecular length of the water soluble organic compound. The solid crystal of the ionic salt is the sediment of part of the ionic salt because the amount of the ionic salt is more than its solubility in the liquid electrolyte.

Abstract: The present claimed invention intends to provide a responsive glass membrane for ion selective electrode glass and an ion selective electrode comprising the responsive glass membrane that produces a self-cleaning function when the ultraviolet rays are irradiated although no change is brought in a composition of a sample solution as being an object to be measured and that is low in electric resistance value and superior in responsivity under an ordinary measurement environment. The responsive glass membrane for ion selective electrode is made of the titanium-containing oxide glass that contains 20˜80 mol % of titanium dioxide and lithium oxide.

Abstract: An apparatus, system and method maximizes efficiency and accuracy of measuring an ion concentration of a measured fluid by varying a flow of ions within a measuring cell (1006) in accordance with an output signal of a sensor cell. The pump current through a pump cell is switched between a constant positive current and a constant negative current when upper and lower thresholds of the output signal are reached. The pulse width ratio of the square wave produced by the varying current is compared to a pulse width ratio function derived from a calibration procedure to determine the ion concentration of the measured fluid. In one embodiment, the functions of the pump cell and sensing cell are performed by a single electrochemical cell. In an embodiment where a concentration of a compound is determined, a primary electrochemical cell system pumps an ion of an element of the compound into and out from a measuring chamber.

Abstract: An ion concentration sensor produces a signal reflective of the ion concentration within a solution. The ion concentration sensor is based on an ion sensitive transistor having a solution input, a reference input, a diffusion input, and a diffusion output. The ion sensitive transistor is connected as a pass transistor, such that the diffusion output provides an electrical signal indicating an ion concentration in a solution contacting the solution input.

Abstract: An ionic probe is provided according to the invention. The ionic probe includes an active electrode configured to generate a measurement signal for an external test fluid, a first reference electrode configured to generate a first reference signal, and an at least second reference electrode configured to generate at least a second reference signal. The measurement signal is compared to the first reference signal and the at least second reference signal in order to determine an ionic measurement of the external test fluid.

Abstract: A system that incorporates teachings of the present disclosure may include, for example, a solid-state selector having a vessel for carrying a liquid medium with one or more molecules surrounded by ions, a solid state conductive structure doped with impurities having one or more through-holes extending between two surfaces of the solid state conductive structure positioned within the liquid medium of the vessel, a voltage source coupled to the solid state conductive structure to selectively stimulate the ions surrounding the one or more molecules to pass through the one or more through-holes. Additional embodiments are disclosed.

Abstract: The present invention provides a catalytic system comprising a catalyst comprising nanoporous or mesoporous palladium and an ion-exchange electrolyte, processes for manufacturing the catalytic system and catalyst, and processes for oxidising or reducing organic and/or inorganic molecules using the catalyst or catalytic system.

Abstract: The measurement instrument includes an attribute information output section to output attribute information about the attributes of the measurement instrument as an electric physical value. The attribute information is based on at least one of the conditions including a resistance of the attribute information output section, a location of the attribute information output section, and the size of a region on which the attribute information output section is formed. The attribute information may be used to select the calibration curve suitable for the measurement instrument. The attribute information may be one that relates to a specific measurement standard applied to the measurement instrument.

Abstract: A unitary ionic probe is provided. The unitary ionic probe includes a substantially elongate body including a central axis (AA), a proximal end, and a distal end. The unitary ionic probe further includes an active ion sensitive region that is located on and bonded into an exterior of the elongate body in a region of the proximal end and an active electrode in ionic communication with the active ion sensitive region. The unitary ionic probe further includes a reference ion sensitive region that is located on and bonded into the exterior of the elongate body and is spaced-apart from the active ion sensitive region and a reference electrode in ionic communication with the reference ion sensitive region.

Abstract: An ionic probe including an extrudable conductive junction material is provided. The ionic probe includes an outer shell holding the conductive junction material and an ionic probe assembly located at least partially within the outer shell, with the ionic probe assembly including an active ion sensitive region extending from a proximal end of the outer shell and further including an active electrode and reference electrode extending from a distal end. The ionic probe further includes at least one moveable seal that forces extrusion of a portion of the conductive junction material.

Abstract: Described herein are substrates, sensors and systems related to measuring the concentration of an analyte such as hydrogen ion in a sample. Redox active moieties whose reduction and/or oxidation potentials are sensitive to the presence of an analyte are immobilized onto a silicon surface. Immobilized redox active moieties whose reduction and/or oxidation potential are insensitive to the analyte can be used for reference. Voltammetric measurements made using such modified silicon surfaces can accurately determine the presence and/or concentrations of analytes in a sample of interest. The silicon electrochemical sensors of the invention are robust and can be made so as not to require calibration or re-calibration.

Abstract: An electrode for superoxide anions characterized by comprising a conductive component and, superimposed on a surface thereof, a film resulting from electrolytic polymerization of a metal thiofurylporphyrin/axial ligand complex; and a sensor for measuring a superoxide anion concentration including the same. The electrode for superoxide anions, by virtue of not only the excellent performance of electrode provided with the metal porphyrin complex polymer film, but also the presence of the axial ligand, can prevent poisoning by a catalyst poison such as hydrogen peroxide. Accordingly, in any of in vitro or in vivo environments, this electrode for superoxide anions enables detection of superoxide anion radicals without suffering any influence from a catalyst poison such as hydrogen peroxide. Moreover, quantitative assay of superoxide anions can be performed by the use of this electrode for superoxide anion in combination with a counter electrode or a reference electrode.

Abstract: The present invention relates to microelectode arrays (MEAs), and more particularly to carbon nanotube nanoelectrode arrays (CNT-NEAs) for chemical and biological sensing, and methods of use.

Abstract: A disposable, self-administered electrolyte test is affixed to the label of a commercially available electrolyte supplement, is available in the pharmacy section of a retail store, or is distributed by a physician or a clinic.

Abstract: A selective gas sensor is for determining the presence of a test gas, for example, helium includes an evacuated housing, sealed by a selectively gas-permeable membrane. The membrane is part of a sight glass, whereby the glass pane is provided with a hole, sealed by the membrane made from a silicon material. The frame of the membrane wall is connected to the housing by means of a high-vacuum soft-metal seal. The housing can also form one of the electrodes of the gas pressure sensor.