Abstract: A body fluid sample is diluted with a diluent which comprises an aqueous solution containing bis(2-hydroxyethyl)-iminotris(hydroxymethyl)methane and boric acid to obtain a diluted body fluid sample, and the ion concentration in the diluted body fluid sample is determined with ion-selective electrodes, whereby the variation width of pH in the diluted body fluid sample can be held down to a narrow range. As a result the determination can be made without exerting adverse effects on the ion-selective electrodes, and errors in determination can be markedly reduced as compared with cases where the conventional diluents are used.

Abstract: A pH sensor has a core of an electrochemically inert insulating or semi-conductive material, and is coated with an electrically conductive, electrochemically sensitive coating. The preferred core is insulating and made of alumina, with a thin coating of iridium oxide deposited over at least a portion of the outer surface of the core. The coating is carried to a surface remote from the sensing surface and is used for making electrically conductive connections that lead to remote circuitry. The core is made in a form that can be supported and held in an insulating, electrochemically inert, deformable material that is sealed around the outer surface of the coating on the core to prevent leakage of chemicals being sensed. The body also permits sealing quite easily onto access ports on which the sensor housing is mounted. Various connections to the electrode coating can be made quite easily to provide for a unique sensor assembly.

Abstract: A sheet-type, highly polymerized composite electrode used for measuring ionic concentration includes a thin film ion-selective responsive membrane formed on an upper surface of an insulating support layer by sequentially dripping an ion-selective responsive membrane paste containing solvent onto the support layer. The ion-selective responsive paste has a polymerization degree sufficient to provide an enduring ion-responsive membrane without any reinforcing structure.

Abstract: A reference electrode according to the present invention includes a silver layer (2) and an insulating hydrophobic material layer (5) which is formed by atomic beam sputtering and containing silver halide dispersed therein, on the surface of a conductive substrate (1).The resulting reference electrode is of a solid type, is almost free from outflow of silver halide, can be miniaturized easily, is not affected by ion concentration, provides a stable potential and has high durability.The conductive substrate (1) may be a field effect transistor having a gate insulator film and the layer (5) may be a laminate film obtained by laminating alternately a thin layer or layers of silver halide and a thin layer or layers of insulating hydrophobic material.

Abstract: A gaseous carbon dioxide detection sensor comprising a detection electrode and a reference electrode opposed on both sides of an ionic conductor, wherein a mixture comprising one mol of an alkali metal carbonate more than one mol of an alkaline earth metal carbonate is used as the detection material for the detection electrode. The detection sensor has the electromotive force characteristic relative to the gaseous carbon dioxide less undergoing the effect of moisture in the gas to be measured and has a high sensitivity.

Abstract: A method for the detection and measurement of a minor element in a molten metal, the minor element being selected from the group of phosphorous, silicon, arsenic, antimony and sulfur, includes providing a first electrical lead (5) and immersing it in the molten metal (6), disposing a solid electrolyte matrix (2) in the molten metal in spaced relationship to the first electrical lead, providing a second electrical lead (3) connected to the solid electrolyte matrix (2) so that the matrix is between and separates the leads when the matrix is disposed in the molten metal, and connecting a voltmeter (7) between the other ends of the electrical leads and measuring the EMF between the leads as an indication of the concentration of the minor element in the molten metal. The solid electrolyte is a matrix (2) of alumina selected from the group consisting of .beta.-alumina and .alpha.+.beta.

Abstract: The present invention provides an ion sensitive film (6) comprising a mixed layer containing a redox manifesting substance manifesting redox function and a polymeric compound containing an ion carrier substance. The present invention also provides a method of producing the ion sensitive film (6) and an ion sensor which uses the film (6). The ion sensitive film (6) of the present invention enables the provision of an ion sensor having excellent durability, preservative stability and sensor characteristics.

Abstract: An electrolytic sensor is set forth for measuring the amounts of an ionic and of a vaporous species in a liquid. The system has an electrode sensitive to an ionic species and another electrode sensitive to a vaporous species. A unitary membrane covers the electrodes and the requisite electrolyte with the membrane being permeable to the vaporous species, impermeable to the liquid and having dispersed in it an ionophore which senses the ionic species via selective transfer into the membrane of a quantity of the ionic species determined by the concentration of the ionic species in the liquid. Such quantities as hydrogen ion concentration, carbon dioxide concentration and oxygen concentration can be determined by a single electrolytic cell structure.

Abstract: In order to reduce the measuring volume in a device for measuring chemical and physical parameters of liquid or gaseous media by means of optical sensor elements whose optodes may be replaced easily, a measuring unit with a sample channel is provided which may be inserted into a supporting frame of the device and which may be connected to ingoing and outgoing sample lines via capillary bores. The measuring unit contains a sensor carrier forming the boundary of the sample channel on one side, which sensor carrier has bores holding the optodes. The indicator film of each individual optode is situated in the plane of the sensor carrier facing the sample channel.

Abstract: A solid state electrode for the determination of sodium ion concentrations in solutions, with a solid state electrolyte having a high conductivity for sodium ions being provided as the sodium sensitive membrane. The solid state electrode and a reference electrode forms a sensor.The advantages of the sensor of invention are, in particular, high selectivity combined with economical production in thick-film technology. The sensor may be constructed in cylindridcal form.

Abstract: A sodium ion sensor having a composite electrolyte is disclosed. The sodium ion sensor has an outer electrolyte which is insensitive to water and has a high transport activity for sodium ions and an inner electrolyte which is a thin membrane having a very high sodium ion selectivity. The sodium ion sensor having such an electrolyte is sensitive only to the transport of sodium ions and may be operated in aqueous solutions without buffering and in the presence of other alkali ions and alkaline earth metal ions. Sensors of this type operate in EMF mode to give a substantially instantaneous determination of the sodium ion concentration of the aqueous medium being analyzed. The sensor may be used as an on-line sensor directly exposed to the medium to be analyzed.

Abstract: The invention relates to an Ag.sub.2 S crystalline membrane, a process for its manufacture, and a process for its use in detecting silver ions or halide ions.The membrane according to the invention comprises silver sulfide doped with an ion capable to form either with Ag.sup.+ or with S.sup.2- a salt much more insoluble than the species in solution. Preferably the membrane further contains an inert hydrophobic compound. The membrane is prepared by coprecipitating silver sulfide with the doping agent, by homogenizing the coprecipitate with the hydrophobic compound and by pressing.The membrane can be used in an electrode to detect silver or halide ions in solution.

Abstract: Ion selective parts are described which comprise a polymeric material, an ion selective component and optionally furthermore a plasticizer and which ion sensitive parts are suited for the determination of the concentration or activity of ions in liquid media. The polymeric material of said ion sensitive parts is a copolymer in which 5-25 mol-% of the monomeric units of said copolymer are substituted with one or more hydrophilic substituents which are selected from the group comprising hydroxy groups, carboxylic acid groups, sulphonic acid groups and phosphonic acid groups. The inventive ion selective parts have, compared with corresponding ion selective parts in which the polymeric material is free of the stated hydrophilic groups or has a lower content of said hydrophilic groups, a better stability of the standard potential E.sub.o and a lower asymmetry potential or no asymmetry potential at all.

Abstract: Disclosed is a sensor device for detecting a specified chemical component of a solution. The sensor device includes an electrode for generating a potential corresponding to a concentration of a specified component of a solution, a reference electrode including a insulated-gate FET having a film insensitive to the component of the solution formed on the gate region, and an electrode for detecting a potential difference between the potential generating electrode and the reference electrode. The insensitive film included in the reference electrode contains a siloxane copolymer.

Abstract: An electrode for measuring the activity of ionic species. The electrode comprises a material which is chemically sensitive to at least one ionic species. The material comprises an insulating component and a conductive component of lower resistivity than the insulating component. The insulating component has a density of proton binding sites sufficiently large to be sensitive to the ionic species. The conductive component comprises particles, the size of which are sufficiently small to modify the bulk conductive properties such that the susceptibility of the particles to redox interference in the operation of the electrode is decreased, while maintaining sufficient conductivity to operate in Faradaic electrode configurations. Illustratively, the insulating component is tantalum oxide, zirconium oxide or aluminum oxide and the conductive component is iridium, platinum, ruthenium, palladium, rhodium or osmium oxide.

Abstract: A method for monitoring low anion concentrations, and particularly sulfate concentrations in aqueous solutions is provided which includes the steps of adjusting the pH of the solution to substantially reduce the presence of hydroxides therein, mixing a nonionic solvent with the solution selected from the group consisting of alcohols, aldehydes, ketones, nitriloes and other water soluble organic compounds which do not contain sulfonate groups, exposing the solution and solvent mixture to an electrode selective for sulfate ions, exposing the mixture to a counter electrode and measuring the difference in voltage across the electrodes. A chilling apparatus may be added to reduce solvent consumption and lower the detection limit.

Abstract: A highly sensitive and reliable electrochemical method is proposed for the determination of the lithium ion concentration in an aqueous medium, e.g., blood of a patient suffering depression and administrated with a lithium-containing medicament, by measuring the electromotive force between the medium and a powdery non-selective electrode, which is a non-stoichiometric composite oxide of lithium and manganese of the formula Li.sub.x Mn.sub.2 O.sub.4, x being a positive number smaller than 1, prepared by partially leaching lithium ions out of a spinel-type lithium manganate LiMn.sub.2 O.sub.4 with an acid, dipped in the medium. The ion-selective electrode can be in the form of a thin film or coating layer on an electrode element. This film or layer can be formed of a polymeric resin as a binder for the powdery composite oxide.

Abstract: An ion sensitive electrode device and method of its use in analytical and clinical chemistry are provided for measuring the concentration of an ionizable analyte contained in an aqueous medium. The device with external circuit means includes an electrode pair adapted to be placed in electrochemical contact with the medium. The electrode pair includes a polarographically active base metal/metal oxide working electrode and a reference electrode. The external circuit means is adapted to measure the voltage generated by the electrode pair in open circuit and to measure the closed circuit current flow at a preselected impedance and including means for comparing said voltage and current flow values with predetermined reference standards to provide a third value representative of said analyte concentration.

Abstract: Novel microelectrochemical devices are provided which consist of closely spaced microelectrodes coated with metal ion based inorganic redox active material such as oxides or mixed oxides of any of the following transition metals: W, Ni, Ru, Co, Rh, Ir, Nb, Mo, V, or any other metal that undergoes a change in electrical conductivity upon electrochemical oxidation or reduction, in contact with an electrolyte. Additionally, other metal based redox materials whose conductivity changes as a function of the movement of ions into or out of the material can be used in the construction of microelectronic devices, for example, Prussian Blue, Fe.sub.4 [Fe(CH).sub.6 ].sub.3."Metal ion-based microelectrochemical devices" encompasses all devices based on an inorganic redox active material which incorporate an active "gate" region or "channel", or exhibit rectification.

Abstract: A portable apparatus for measuring the electrochemical characteristics of a sample is disclosed. A disposable cartridge, including a plurality of interconnected flow chambers, houses a printed circuit board substrate upon which reference and indicating electrodes are formed. The electrodes are employed in the presence of chemical reagents to aid in the electrochemical determination of a sample undergoing analysis. A thermal sensing element is in close proximity to the electrodes to permit the correction of the measurement for variations in temperature. After a pH value has been determined, the used cartridge can be mechanically ejected thus eliminating user exposure to the blood sample being measured. In this way, the pH of a blood sample can be determined quickly, effectively, inexpensively and with a minimum amount of sample and reagent preparation.

Abstract: An ion selective electrode flow cell includes a first fluid conduit and at least two ion sensing electrodes each having ion sensing surfaces disposed within the first fluid conduit. A second fluid conduit and an ion sensing electrode having an ion sensing tip is disposed within the second conduit. There is an electrically conducting bridge connecting the first and second fluid conduits. A conductive member is disposed within the first fluid conduit proximate the ion sensing surfaces of two ion sensing electrodes and the bridge. A third fluid conduit may intersect the first fluid conduit and can include grounding for grounding fluid flowing through the third fluid conduit. Capacitors between exit and entry ports of the first and second fluid conduits and ground reduce electrical noise within the flow cell.

Abstract: Electrochemical microsensors formed of a substrate containing means for sensing potential or current, including active and passive electronic devices and electronic circuits, and a micromachined structure containing at least one cavity overlying the sensing means, wherein the structure and substrate are bonded together at a temperature less than about 400.degree. C., in the absence of high voltage fields, using means not requiring highly planarized surfaces. A wide variety of materials can be utilized for both the substrate and overlying structure.Diverse embodiments are possible, having in common a cavity containing a chemically sensitive material and means for sensing potential or current.The resulting structural organization of materials transduces a chemical signal, such as concentration, to an electrical signal, which is then "processed" by the underlying FET or metallic connections.

Abstract: The electrode comprises an internal reference half-cell at stable potential comprising a conductive sheet, e.g. of metal of carbon, covered by a redox system. The redox system comprises a thin dehydrated layer of Prussian blue deposited by contact between the sheet and a mixture of alkaline ferrocyanide and a ferric salt.

Abstract: A real time, on-line ion mesurement system for a solution has continuous monitoring of the physical conditions of the ion electrode and the reference electrode of the system. A dual chamber reference electrode is provided having an inner chamber and electrode for providing an ion measurement reference potential, and an outer chamber and electrode for producing a monitoring potential to detect poisoning of the reference electrode membrane. A first time varying low level signal is applied to the ion electrode and a second time varying low level signal orthogonal to and uncorrelated with the first signal is applied to a solution ground electrode disposed in the solution adjacent the reference electrode, the signals producing a composite common ground current. A pair of cross-correlators extracts the two time varying components from the common ground current for measuring the ion electrode and reference electrode impedances.

Abstract: An improved electrode assembly for measuring ions, such as a pH electrode, and method of forming the same is provided. A plastic support layer with an aperture is mounted over a base member having electrodes. A gelatinized internal solution is mounted in the aperture over the electrodes in a plasticized solution containing a hydrogen ion-responsive material is formed into a paste and is positioned over the gelatinized internal solution and the adjacent surrounding areas of the support layer. When the paste solidifies it forms a thin film plastic ion-selective response membrane that is integrally sealed to the support layer.

Abstract: An ion selective electrode apparatus for measuring ion activity of solution flowing through a conduit, wherein at least one earth electrode is disposed so as to contact the solution. The earth electrode is capable of shunting electrical noise flowing through the conduit to earth. In the preferred embodiment, an ion selective electrode and a reference electrode are disposed along the conduit between two earth electrodes so as to protect the ion selective and reference electrodes from the electrical noise which may be introduced into the ends of the conduit.

Abstract: There are disclosed a process and the product produced by the process, of making an ion selective electrode for chloride. The process features, after forming a metal chloride layer, the step of washing the electrode in an organic acid, inorganic acid, or a solution of a salt of the acids having certain specified properties.

Abstract: An ion-sensitive measuring electrode device with an ion-sensitive element based on ion-conducting crystalline ceramic material is provided. The electrode device shows a selectivity to the Na.sup.+ ion versus the H.sup.+ ion corresponding to the selectivity of the known sodium-sensitive glass-based solid membrane electrodes.Ion-sensitive measuring electrode devices showing good selectivity properties are provided on the basis of ion-conducting crystalline material, the crystal structure of which comprises a three-dimensionally extending interstitial space containing positions for the ion, especially material in which the interstitial space has bottlenecks which just permits passage of the ion.A method for preparing polycrystalline ceramic material based on oxides of zirconium, phosphor and silicon is also provided.

Abstract: Hematocrit level of a blood sample is measured by flowing the sample along a liquid flow path and using electrodes in the flow path to obtain electrical signals representative of the sample's electrical conductivity and of the concentration of an ion species in the path, either before or after the sample measurement. Electrical signals are obtained for standardizing solution conductivity and ion species concentration. A tentative sample hematocrit value is derived from the sample and standardizing conductivity signals. Then the tentative hematocrit value is corrected with reference to the sample and standardizing ion concentration signals and to the known standardizing solution ion concentration value. A control solution of the ion species at known concentration is used for evaluating the hematocrit detection apparatus; the solution also includes an ion activity enhancing agent.

Abstract: A conductive layer is formed on an insulating base, and at least one groove is formed in the conductive layer by cutting a part of the material of the conductive layer so that the conductive layer is divided into at least a pair of portions electrically isolated from each other by the cut groove. Thereafter, an ion selective layer is formed on the conductive layer to cover substantially the entire surface of the conductive layer including the cut groove.

Abstract: An ammonia gas sensor comprises a dual gate field effect transistor (FET) in which the two gate electrodes are of platinum deposited respectively by sputtering and evaporation. The gate regions of the two FETs are connected together differentially and the net drain source voltage represents the concentration of ammonia gas to which the sensor is exposed.

Abstract: An ion selective electrode device, in particular a pH-sensitive electrode device, employing an intercalation electrode (3) as contact material between an ion selective element (2) and an electrical connection (9).An intercalation electrode comprising an equilibrium mixture of two phases, at least one of the phases working as an intercalation electrode, is disclosed.The electrode device may be constructed as a solid state electrode device showing advantageous electrode properties.

Abstract: A device for the measurement of ionic and gas species at high temperatures. Platinum metal oxides are used for the electrical signal paths between electrical elements on the device to make the device particularly adaptable to high temperature measurement applications. Chemically sensitive composite structures may be hardened for high temperature applications by mixing polyimide with the materials normally used in the outer layer of such structure.

Abstract: An analyte sample of blood serum is reacted with a protease in excess over that quantity required to provide a 1:1 protease:inhibitor complex. The excedent protease is then back-titrated using the reaction with diphenylcarbamyl fluoride and measuring electrometrically the liberated fluoride.

Abstract: An integral ion selective electrode for the analysis of a potassium ion comprising a support, an electroconductive metal layer such as a silver metal layer, a layer of a water-insoluble salt of said metal such as a silver chloride layer, an electrolyte layer which comprises an electrolyte salt of a potassium ion with the same anion as the anion of the water-insoluble salt, said electrolyte layer being substantially free from a binder, and an ion selective layer, which is characterized in that the electrolyte layer comprises crystalline electrolyte having a mean crystal size of not more than 60 .mu.m. Processes preferably employable for the preparation of the ion selective electrode are also disclosed.

Abstract: An electrode system for an electrochemical sensor has a plurality of electrically conductive sensing segments isolated from each other and mounted on a support substrate formed from a chemically inert encapsulation material. The sensing segments are unencapsulated and are each coated with respective ones of ion conducting sensing materials to characterize each of the segments except for one of the segments which is uncoated and is arranged to be used as a reference electrode. The outer surface area of the sensing materials and the reference electrode is coated with a layer of a nonaqueous electrolyte which serves as a sorption/desorption medium. The electrolyte, in turn, is covered by a semipermeable thin film membrane secured at its peripheral edge by an O-ring to the support to form a fluid seal. Electrically conductive leads are connected to respective ones of the sensing surfaces, and a temperature measuring device is provided in the electrode structure for temperature compensation.

Abstract: A solid state electrode that includes a graphite core as both the internal reference and the electrical conductor that is preferably formed of graphite threads maintained as a bundle that in one embodiment, has an end thereof coated with a mixture of antimony and antimony oxide as a sensor element, the graphite junction forming the internal reference to that sensor element, and in another embodiment, the graphite core is wrapped tightly around a sensor formed from section or "shot" of a mixture antimony and antimony oxide, the graphite junction forming the internal reference thereto. The connected graphite core and antimony/antimony oxide sensor are then covered with an impermeable non-conductive plastic sheath, leaving a section of the antimony/antimony oxide sensor surface exposed, and the junction of that sheath to the antimony/antimony oxide sensor is preferably sealed as with an epoxy.

Abstract: The intermittent electrolysis of a portion of the used ammoniacal etching solution generates oxygen at the anode which is mixed into the remainder of the circulated etching solution for reoxidation and regeneration before it is returned to the etching chamber. The portion of the solution which goes through the electrolysis cell, and has its metal content reduced, is returned to the beginning of the circulation loop rather than to the etching chamber, in order that the metal content of the circulated solution may be quickly reduced. This reduction is quickly picked up by a metal content measuring device in the branch supplying solution to the electrolysis cell.

Abstract: Electrochemical cell including an ion-specific membrane containing, in one aspect, Ag, S, and Sb and in another aspect a ternary compound of Ag, S and one of As, Sb, Se and Te. Methods are disclosed for making ternary compounds of Ag, S and one of Se, Sb, Te and As.

Abstract: An ion selective electrode comprising a support having provided thereon, in sequence, a conductive layer and an ion selective layer, which is characterized by having at least one groove through the conductive layer and covering the surface of the groove with the ion selective layer is disclosed. Half cells or electrodes useful for the measurement of ionic activity of chlorine, sodium, potassium or, carbonate or hydrogen carbonate ions in blood or other aqueous sample liquids can be prepared in an extremely simple manner. The single ion selective electrode element comprising paired ion selective electrodes in accordance with the present invention are electrochemically equivalent. A process for forming the same is also disclosed.

Abstract: An ionic activity measuring device comprising a substrate provided with at least one opening for receiving a terminal made of a metal layer or a metal layer and a water insoluble metal salt layer, an ion selecting layer positioned on or in the substrate, and at least one liquid receiving hole for bringing liquid into contact with the ion selecting layer at the point vertically aligning with the opening in the substrate. The liquid receiving hole is formed in a porous bridge positioned on the ion selecting layer or on a bridge supporting material which is discrete from the ion selecting layer, or is formed in the substrate. The substrate may be a flexible film, and the device may further comprise a film feeding housing provided with a shaft for feeding the film and a film receiving housing provided with a wind-up shaft.

Abstract: A chemical sensing element suitable for measurement of the activity or the concentration of a specific ion contained in an electrolyte is provided with an optically opaque membrane between a gate insulating membrane and an ion sensing membrane of a field-effect type transistor. Since the opaque membrane is provided, extraneous light impinging on a gate is blocked by the opaque membrane, whereby an erroneous potential due to extraneous light is prevented. Accordingly, the accurate measurement of the activity or the concentration of a specific ion contained in an electrolyte may be achieved even in intense ambient light.

Abstract: A chemically sensitive device for monitoring chemical properties is described. The device includes a depletion-mode field-effect transistor. Two electrical leads are connected between source and drain region of the field-effect transistor to monitor changes in current or potential resulting from changes in the amount of chemical to be monitored. A reference electrode is attached to a lower substrate surface of the field-effect transistor and electrically connected to the source via a highly doped region adjacent to the source and another highly doped region adjacent to the reference electrode, both having a polarity identical to the substrate. A sensing membrane which is specific to the chemical to be monitored is located on a portion of the substrate remote from the gate region but electrically connected to the gate region to alter conductance between the source and the drain in accordance with the presence or absence of the chemical to be monitored.

Abstract: The invention provides a chemical-responsive field-effect transducer operating in depletion-mode, or enhancement/depletion-mode, comprising: a semiconductor material having a pair of adjacent diffusion regions (1,2) of a certain doping polarity located at the surface and separated by a channel (3) of the same doping polarity, said channel being created by diffusion, ion-implantation, epitaxial growth, or creation of a surface inversion layer by controlled processing techniques or other means. The diffusion regions and channel region are supported by an insulating substrate (4) or semiconductor substrate of opposite polarity. Electrical insulator (6) and/or ion-barrier material (7) overlies the aforementioned channel region. An electroactive material (10) overlies said insulator and/or ion-barrier, such that the electroactive material will interact with substances to which it is exposed and control the charge-carrier density in the aforementioned channel.

Abstract: An electrochemical electrode device comprising a tubular member having a bottom end adapted to be inserted into a liquid sample to be measured, and a top end which is closed by a cap member including electrical conductors by means of which the electrodes of the electrode device are connected to an outer cable. In order to facilitate the introduction of liquid or gel into an inner space defined within the tubular member as well as withdrawal of liquid or gel from that space, a longitudinally extending passage is formed within the cap member. This passage may be selectively opened and closed by means of a closure member which is received in a cavity extending transversely to and intersecting the longitudinal passage. The closure member is preferably in the form of a swingably mounted slide valve member or a rotatable cock member.

Abstract: A device is disclosed for determining the ionic analyte activity in liquids, e.g. aqueous solutions, by the use of electrodes and an internal capillary bridge which promotes ionic migration between the electrodes. This device includes an electrically insulative frame in which the electrodes are mounted, liquid access holes aligned with the electrodes on a capillary bridge formed of a porous material, and a cover sheet element formed of a nonporous cover sheet. The cover sheet element extends over the electrodes and encapsulates the elongated capillary bridge. Located in the cover sheet directly over and generally along the capillary bridge is one or more substantially continuous stretch lines typically provided by mechanically deforming the cover sheet. This deformation allows shorter junction times when liquids are introduced into the liquid access holes.

Abstract: An ion-sensitive electrode, usable for measuring the activity or concentration of a predetermined ion in a fluid stream of an industrial process, includes a vessel partially filled with an electrolyte and fabricated with one wall portion thereof comprising a rigid, porous fritted back-up element and a relatively thin, ion-sensitive, non-porous membrane. Being preferably made of the same ion-sensitive material as the membrane, the back-up element is produced using a sintering process which results in a porous solid having maze-like passages extending randomly therethrough in all directions. One surface of the back-up element is fused to and supports a thin layer of ion-sensitive material that has been applied to the back-up element, heated to its molten working temperature and then cooled to form the non-porous membrane. Located within the vessel, the back-up element also serves to transport the electrolyte through its passages for wetting the interior surface of the thin membrane fused to the back-up element.

Abstract: In the formation of a chemically sensitive field effect device, prior to formation of the gate membrane, an aluminum pad is disposed over the gate, and a polyimide layer is disposed thereover. Photoresist and etching steps produce openings in the polyimide to form a gridwork which is anchored to the device on the periphery of the gate. The aluminum layer is etched completely away, forming a void defined by the suspended polyimide mesh on one side, and the gate insulator on the other. Polymeric membrane is formed in the void by insertion in liquid form.

Abstract: An ion sensor and more particularly ion sensitive field effect transistor comprising an inorganic film, and an impurity layer formed in at least surface layer of said inorganic film by thermal diffusion or ion implantation.

Abstract: A measuring electrode device comprises a pH electrode arranged within an outer casing and having a pH sensitive member in contact with an electrolyte housed in the outer casing. The electrolyte reacts with a predetermined gas in a liquid to be inspected and varies its pH. The pH sensitive member includes a semiconductor substrate and a pH sensitive membrane formed on the substrate and in contact with the electrolyte. The pH sensitive membrane is formed of at least one element selected from the group consisting of silicon nitride, aluminum oxide and tantalum pentoxide. A potential difference is produced between the pH sensitive membrane and the electrolyte in accordance with the variation of the pH of the electrolyte. Thus, a potential difference is produced between the pH electrode and a reference electrode according to the variation of the pH of the electrolyte.