Abstract: An electrophoretic system employing a capillary with at least one end having an electrically conductive coating or layer directly thereon. In order to introduce a plug of sample from a small amount of the sample in a vial, the conductive tip is submersed into the small amount of sample and an electric field is applied at the end by applying the high voltage to the tip in order to electrokinetically inject a plug of the sample. The conductive tip may also be used as a terminal for completing the circuit for applying the high voltage across the capillary column for electrophoresis. The separated components may be collected on a surface or small amount of buffer to reduce sample dilution or mixing of one sample component with a different sample component from the electrophoretic process.

Abstract: A PH measuring device having a first and second lumen with adjacent first ends, wherein the first lumen has a sensor electrode secured to the first end and the second lumen has a fibrous absorbent plug closing the first end, with an absorbent thread attached to the plug, and extending through the second lumen. An electric conductor connected to the sensor electrode extends through the first lumen to an electrical meter.

Abstract: A titration electrode device for measuring the amount of a species in solution in a test liquid comprises a counter electrode and a generator electrode both in a chamber for receiving a thin layer of test liquid, the two electrodes being located in respective compartments within the chamber such that ionic conduction between the compartments is permitted but diffusion of electrogenerated reagents between the compartments is restricted, the device including reference and sensor electrodes in the chamber.

Abstract: A CO.sub.2 electrode can be calibrated with two PCO.sub.2 calibration standard solutions having known pH values and known bicarbonate ion source concentrations. An O.sub.2 electrode can be calibrated using air as one calibration standard and a solution containing an excess of an O.sub.2 depleting agent as a second calibration standard.

Abstract: This invention relates to a pH measuring electrode having a sensor film which is sensitive to a hydrogen ion (H.sup.+) in the solution. The pH measuring electrode of this invention has a sensor film of a metal oxide deposited on an electrically insulative ceramics substrate so that the sensor film can be very miniaturized in its size. Therefore, the entire pH measuring electrode can be made considerably small and simple in construction. Also, this invention provides another pH measuring electrode which further includes a porous film of an insulation material coated on the surface of the metal oxide sensor film so that the sensor film is not affected by any coexistent substances.

Abstract: Electrochemical sensors and methods for their use are provided for the detection of the pH and/or oxygen concentration in an aqueous medium. The subject sensors comprise a closed-end cylinder shaped fluoride based solid-state electrolyte having an inner and outer surface. In contact with the inner surface of the electrolyte is a solid reference electrode. In a preferred embodiment, the electrolyte is described by the formula La.sub.0.95 X.sub.0.05 F.sub.2.95, wherein X is an alkaline earth metal. In addition to finding use in the detection of the pH or oxygen concentration of a medium where one these factors is known, at least two of the subject sensors may be used in conjunction, where the reference electrode differs between the two sensors, to determine the pH and oxygen concentration of a medium where both of these values are unknown.

Abstract: A method for assaying an enzyme on a targeted solid body surface, including the steps of contacting an end opening of a thin tube with a targeted solid body surface to form a space between the targeted solid body surface and inner wall surface of the thin tube, supplying a substrate solution into the space to bring the substrate solution in contact with the targeted solid body surface, and determining a pH change of the substrate solution in the space by using a pH electrode; and an apparatus therefor.

Abstract: A planar bicarbonate sensor has been discovered that has a dried residue internal electrolyte layer comprising a bicarbonate source and a halide salt of potassium, lithium, or sodium. The flow-through sensor is capable of providing bicarbonate level of a liquid sample, and when coupled with a pH sensor, may be used to determine the partial carbon dioxide level in the sample. The sensor provides many commercially desirable characteristics including an adequate lifetime, good response time, and good stability upon first usage.

Abstract: An automatic calibrating apparatus for a measurement instrument having a sensor member includes a chamber adapted to hold the sensor member during a storage mode. A controller can respond to the presence of the sensor member and automatically wash the sensor member, and subsequently immerse it in a calibration solution. The output reading of the sensor member, along with the temperature, can then be utilized to calibrate the instrument. The sensor member can be subsequently cleansed with a washing fluid so that it is ready for immediate use.

Abstract: A reactant monitoring system for monitoring certain properties of, e.g. a BHP reactant solution is provided. Such system incudes a diagnostic conduit loop having one or more sensors in the conduit to measure, e.g. pH and/or ORP of such solution. The solution is pumped through the conduit loop by a pump and the sensors are preferably mounted in the loop, upstream of such pump. The sensors are made of inert materials relative to the monitored solution in the loop, which solution is returned to its source after testing.

Abstract: A member has a solid carrier and a thin oxide layer which is arranged thereon and consists of iridium oxide and/or possibly at least one oxide of at least one other metal belonging to the fifth or sixth period and to one of the subgroups 5b, 6b, 7b and 8 of the Periodic Table of chemical elements and/or zirconium oxide. The oxide layer is monocrystalline and therefore very stable. The member can serve, for example, for the formation of at least one electrode which serves as a proton donor and/or proton acceptor and/or for the measurement and/or change of the pH value and/or for a coulometric measurement or for holding biologically active molecules and at the same time as an electrode and/or optical sensor.

Abstract: Novel calibration solutions are provided which are useful, for example, with sensor assemblies used for analysis of CO.sub.2, and optionally, for concurrent analysis of O.sub.2, especially in combination infusion fluid delivery/blood chemistry analysis systems which include a sensor assembly with each of the assembly electrodes mounted in an electrode cavity in the assembly. The analysis system used in the practice of the present invention typically includes provision for delivering infusion fluid and measuring blood chemistry during reinfusion of the physiological fluid at approximately the same flow rates. The invention calibration solutions are useful for calibrating an array of sensors capable of simultaneously measuring a number of blood chemistry parameters, including the partial pressures (tensions) of carbon dioxide and oxygen, pH (hydrogen ion), sodium, potassium, ionized calcium, ionized magnesium, chloride, glucose, lactate and hematocrit, in body fluids.

Abstract: This invention relates to a pH measuring electrode having a sensor film which is sensitive to a hydrogen ion (H.sup.+) in the solution. The pH measuring electrode of this invention has a sensor film of a metal oxide deposited on an electrically insulative ceramics substrate so that the sensor film can be very miniaturized in its size. Therefore, the entire pH measuring electrode can be made considerably small and simple in construction. Also, this invention provides another pH measuring electrode which further includes a porous film of an insulation material coated on the surface of the metal oxide sensor film so that the sensor film is not affected by any coexistent substances.

Abstract: A small oxygen electrode and a method of bonding a fluorine resin film are disclosed. This small oxygen electrode includes a flat electrode substrate having at least two electrodes (a working electrode and a counter electrode) formed thereon, and a container substrate having dents formed to confront the two electrodes and contain an electrolyte therein. The container substrate is bonded to the flat electrode substrate, so that the dent confronting the electrode constituting the working electrode has a through hole extending to the side opposite to the flat electrode substrate and a gas-permeable film is formed to cover the through hole. By using this dent structure, the preparation of an oxygen electrode can be conducted while maintaining a wafer form throughout the process, and formation of an electrode pattern can be facilitated.

Abstract: An ion-selective reference probe which is adapted for use with potentiomec measurement systems is disclosed. The reference probe is non-chloride based and employs a specially adapted electrolyte which is reversible (i.e. with regard to ionic activity). More particularly, the electrolyte includes appropriate concentrations of ethylenediamine and copper(II) ions in a solvent to permit reversibility of the electrolyte within a desired range. Junction potential between the electrolyte and a test solution is minimized by forming the electrolyte from a portion of the test solution.

Abstract: A small glass electrode and process for preparation thereof are disclosed. This small glass electrode is characterized in that said glass electrode, which has a bonded structure comprises a reference electrode composed of silver/silver chloride, a glass substrate having a pad embedded therein, said pad being composed of gold or platinum and circuit-connected to the reference electrode, and a silicon substrate having a (100) plane selectively etched by the anisotropic etching technique and comprising a groove for injecting an electrolyte composed of an aqueous solution containing chlorine such as KCl, or HCl, at least one hole for holding the electrolyte and a glass film formed in a portion corresponding to the reference electrode. By this structure, the small glass electrode can be easily manufactured at a low cost.

Abstract: A hydrogen rod electrode including a hydrogen electrode in one aperture of a gas tube, which is connected at the other aperture to a cell holder for containing a hydrogen generation cell. This is used as a reference electrode for electrochemical measurements or as a pH measuring electrode. Through an electric circuit, which is also integrated, hydrogen is provided in adequate quantities for the operation concerned.

Abstract: A reference electrode including a body, a supply of flowable gel electrolyte, a wire electrode, and a tube for the electrolyte. The electrolyte is preferably contained in a cartridge within the body of the electrode and is capable of being dispensed into the tube in very small, metered, amounts, as needed.

Abstract: A working micro-electrode with a reference electrode prepared by coating a working micro-electrode with an insulating material except a working electrode portion, forming a silver layer on the coated surface, and then changing a portion of the silver layer into silver chloride which is the reference electrode; a working micro-electrode with a reference electrode and a counter electrode prepared by coating the working micro-electrode with the reference electrode with an insulating material, and then forming the counter electrode on the surface of the insulating material; and methods for preparing these composite micro-electrodes.Heretofore, even if the working electrode is thinly constituted, the merit of the micro-electrode has not been sufficiently utilized, since the reference electrode and the counter electrode have been thick. However, the present invention can solve this problem and can facilitate experiments in which the micro-electrode is necessary.

Abstract: A planar gas sensor, in particular a pCO.sub.2 or pO.sub.2 sensor, has the following components: a pH sensor located on a flat substrate, or at least one noble metal electrode located on the substrate; a reference electrode adjacent to the pH sensor or noble metal electrode; an electrolyte layer, covering the reference electrode and the pH sensor or noble metal electrode, which is delimited by a first polymer structure; and a layer of hydrophobic material, covering the electrolyte layer and a surface region of the substrate outside the first polymer structure, which is delimited by a second polymer structure.

Abstract: A half-cell reference electrode comprises an electrode member in electrochemical contact with at least one gelled electrolyte solution which itself is contactable with the liquid to be tested wherein the gelling agent comprises a polymer containing acrylamide units substituted with a group or groups which lower the polymer's tendency to hydrolyse compared to polyacrylamide while providing a polymer that can form a gelled solution in 2.6M sodium/potassium nitrate solution (2.21M potassium nitrate and 0.39M sodium nitrate) comprising at least 75% (w/w) sodium/potassium nitrate solution.

Abstract: A pH electrode suitable for in vivo use is provided in a cannula 10, and comprises a reference electrode 14 consisting of a chloridized silver wire surrounded by a solid unbuffered internal reference material 16 comprising potassium chloride, silver chloride, citric acid and sorbitol as a hygroscopic agent. The material 16 is surrounded by a PVC sleeve 12. The tip of the cannula 10 has a pH sensitive polymer-based membrane 20 across its end. The reference material has a pH when hydrated of about 2 which is below the range of pH response of the membrane 20.

Abstract: A sensor for detecting a carbonic acid gas dissolved in body fluids has a laminated structure including an outer plate having a carbonic acid gas permeable window, a plate for a pH-electrode having a pH sensitive membrane, an intermediate plate having a cavity for accommodating an electrolyte, and a plate for a reference electrode. The plate for the pH-electrode is constituted in a manner that a pH sensitive membrane constituted by a membrane of an oxide of a platinum group metal is formed on an insulating substrate and the electrolyte contacts with the pH sensitive membrane in a groove. The pH sensitive membrane is disposed so as to oppose to the carbonic acid gas permeable window.

Abstract: An electrochemical sensor wherein the salt bridge is a unitary plug of semipermeable material which is saturated with an electrolyte. The plug has a spiral cut from its outer surface to the central bore of the plug. The spiral has at least one complete turn and starts at or near one end of the plug and stops at or near the other end of the plug. A layer of impermeable material is deposited in the plug to thereby form an ion impermeable spiral barrier.

Abstract: An automatic control system for maintaining the quality of water in a cooling tower utilizes a probe (38) which senses the oxygen reduction potential (ORP) of a soap having a 1:1 stoichiometric equivalent of an organic acid and ammonia in the water. The soap is pumped from a chemical supply means (20) containing the soap in response to the ORP of the soap in the water falling below a predetermined threshold. A second sensing probe measures the conductivity (in MHos) of the water as a factor of the total dissolved solids (TDS) to control the bleed-off or blow-down of the water. The chemicals, which are supplied for maintaining the ORP, permit significantly higher total dissolved solids in the water than with standard cooling tower systems, without the buildup of scale. As a consequence, water consumption is significantly reduced; and the system functions automatically, without requiring periodic visual inspection, water analysis or manual operation.

Abstract: An improved electronic wiring board having a thermistor and at least one blood gas sensor supported, in close relation, one to the other, on one side of the board and a heater supported on the other side of the board to provide heat in response to temperature sensed by the thermistor, to at least the region where the thermistor and the blood gas sensor are positioned on the board to control the temperature of the region of the board within a narrow distribution of temperatures.

Abstract: A method and apparatus for the monitoring and control of concentration of an ion in a solution at an elevated temperature of at least 100.degree. C. are disclosed. The method comprises the steps of contacting a first electrode with a flowing first solution containing said ion at the elevated temperature, and contacting a second electrode with a second flowing solution containing said ion at the elevated temperature. The rate of flow of the second solution is substantially lower than the rate of flow of the first solution. The first and second solutions are then contacted or admixed. The electrodes must be capable of detecting the ion at the elevated temperature and have the same response characteristics to changes in concentration of the ion at the elevated temperature.

Abstract: The sensor apparatus of the present invention includes on a nonconducting substrate electrically conductive pathways leading to at least two analyte electrodes and one reference electrode. The analyte electrodes each have sensitivities for both analytes but each has a membrane and/or electrolyte that favors the conversion of ionic potential to electronic potential for a different analyte. The apparatus has an fluid circuit means for liquid contact between the electrodes so that electric signals can be sent by electric circuitry to an analyzing means.

Abstract: An automatic control system for maintaining the quality of water in a cooling tower utilizes a probe (38) which senses the oxygen reduction potential (ORP) of a soap having a 1:1 stoichiometric equivalent of mineral acid and ammonia or amine in the water. The soap is pumped from a chemical supply means (20) containing the soap in response to the ORP of the soap in the water falling below a predetermined threshold. A second sensing probe measures the conductivity (in MHos) of the water as a factor of the total dissolved solids (TDS) to control the bleed-off or blow-down of the water. The chemicals, which are supplied for maintaining the ORP, permit significantly higher total dissolved solids in the water than with standard cooling tower systems, without the buildup of scale. As a consequence, water consumption is significantly reduced; and the system functions automatically, without requiring periodic visual inspection, water analysis or manual operation.

Abstract: Novel calibration solutions are provided which are useful, for example, with sensor assemblies used for analysis of CO.sub.2, especially in combination infusion fluid delivery/blood chemistry analysis systems which include a sensor assembly with each of the assembly electrodes mounted in an electrode cavity in the assembly. The analysis system used in the practice of the present invention typically includes provision for delivering infusion fluid and measuring blood chemistry during reinfusion of the physiological fluid at approximately the same flow rates. The invention calibration solutions are useful for calibrating an array of sensors capable of simultaneously measuring a number of blood chemistry parameters, including the partial pressures (tensions) of carbon dioxide and oxygen, pH (hydrogen ion), sodium, potassium, ionized calcium, ionized magnesium, chloride, glucose, lactate and hematocrit, in body fluids.

Abstract: This invention relates to a pH measuring electrode having a sensor film which is sensitive to a hydrogen ion (H+) in the solution and method of manufacturing the same. The pH measuring electrode of this invention has a sensor film of a metal oxide deposited on an electrically conductive support so that the sensor film can be very miniaturized in its size. Therefore, the entire pH measuring electrode can be made considerably small and simple in construction. Also, this invention provides another pH measuring electrode which further includes a porous film of an insulation material coated on the surface of the metal oxide sensor film so that the sensor film is not affected by any coexistent substances.

Abstract: The concentration of an ionic species (e.g. K.sup.+) is determined using an ion sensitive electrode having an appropriate membrane (e.g. valinomycin in plasticised PVC). In place of a conventional reference electrode, the half cell is completed with an electrode having an identical membrane but lacking the constituent producing the ion-selective response (e.g. plasticised PVC). The working and reference electrodes can then be made in substantially the same manner to null of interferents. The difficulties associated with double junctions are avoided.

Abstract: The invention relates to a method of determining an ion concentration with the aid of an ion-selective electrode, in which method a known quantity by volume of a sample is taken, a buffer is added and the initial potential of the electrode pair is measured, a known volume having an accurately known ion concentration is added and the potential obtained is measured, the standard solution being added stepwise, and the initial potential of the electrode pair and the slope of the relationship between potential and logarithm of the concentration is calculated for each of the quantities added from the data obtained, a small quantity of the solution to be determined is added, the potential difference is measured and the latter is compared with the required sudden change in potential, after which a sample is again taken and a quantity of the solution to be determined is added which is expected to bring the sudden change in potential into the required region, the potential is then read off and the required concentratio

Abstract: An improved compact ion-concentration measuring apparatus having a removable sample testing module with gelatinized electrodes. The gelatinized portion of the electrodes can be formed with a jelly containing an acrylic polymer with sodium.

Abstract: Ion sensor having an ion-selective electrode and a reference electrode, both being unified, without internal liquid solution. The ion-selective electrode part has a solid solution of halogenide of conducting ions of solid electrolyte and halogenide of metal for an internal electrode, e.g., NaCl-AgCl solid solution. The reference electrode part has a solid solution of halogenide of the group Ia or IIa, e.g., Na, K, and a halogenide of metal for an internal electrode, e.g., NaCl-AgCl solid solution. The electrode parts are supported by an insulating substrate. A solid electrolyte such as NASICON or ionophore such as valinomycin is used as an ion-sensitive membrane.

Abstract: A corrosion sensor array incorporating individual elements for measuring various elements and ions, such as chloride, sulfide, copper, hydrogen (pH), etc. and elements for evaluating the instantaneous corrosion properties of structural materials. The exact combination and number of elements measured or monitored would depend upon the environmental conditions and materials used which are subject to corrosive effects. Such a corrosion monitoring system embedded in or mounted on a structure exposed to the environment would serve as an early warning system for the onset of severe corrosion problems for the structure, thus providing a safety factor as well as economic factors. The sensor array is accessed to an electronics/computational system, which provides a means for data collection and analysis.

Abstract: In a miniaturizable, capacitively measuring chemical semiconductor-based sensor system consisting of a sensor and a reference element which are to be brought into contact with the electrolyte to be measured, the reference element being connected in series with the sensor, the reference element consists of a highly doped semiconductor substrate or metal/semiconductor substrate which is covered with a membrane, and the sensor consists of an insulator/semiconductor substrate which is coated with a sensitive membrane, and the sensitive membrane of the sensor is more sensitive than that of the reference element.The sensor and the reference element of this sensor system may either be applied to one and the same chip or consist of individual components which are readily interchangeable with one another.

Abstract: A glass pH electrode which comprises a silver-silver chloride or a mercury-mercurous chloride inner electrode and an electrode filling solution for the inner electrode which is a zwitterionic buffer solution containing chloride ions.

Abstract: An apparatus and method for measuring the buffering capacity of a liquid which utilizes a pH electrode positioned at the surface of a working electrode. Measured changes in pH of the metal-water interface at known potentials which are applied to the working electrode are used to calculate the liquid buffering capacity.

Abstract: A fluid sample collector, sensing, and calibration device contains a collector like a syringe, with one or more analyte sensors, and a calibrator for calibrating the sensor. These can be pre-assembled and are particularly adapted to be disposable after a single use; the analyte sensor may be connected to a self-contained monitoring instrument or analyzer which processes the signals from the sensor and displays the information to the operator.

Abstract: A glass pH electrode which comprises a silver-silver bromide inner electrode and an electrode solution for the inner electrode which is a zwitterionic buffer solution.

Abstract: A solid state pH sensor having an indicator electrode of metal/metal oxide and a reference electrode of metal/metal salt applied to inert, electrical conductors imbedded in an electrically non-conductive substrate, such as a ceramic substrate. The sensing portion of the sensor preferably has a coating of an annealed perfluorocarbon copolymer. Alternatively, the indicator or reference electrodes may be formed on separate electrically non-conductive substrates with each having an inert electrical conductor imbedded therein. These indicator or reference electrodes may be utilized with each other or with prior art electrodes.

Abstract: An automatic control system for maintaining the quality of water in a cooling tower utilizes a probe which senses the oxygen reduction potential (ORP) of the water for activating a chemical supply means, in accordance with a pre-established ORP measurement, to maintain the ORP of the cooling tower water between lower and upper limits. A second sensing probe measures the conductivity (in MHos) of the water as a factor of the total dissolved solids (TDS) to control the bleed-off or blow-down of the water. The chemicals, which are supplied for maintaining the ORP, permit significantly higher total dissolved solids in the water than with standard cooling tower systems, without the buildup of scale. As a consequence, water consumption is significantly reduced; and the system functions automatically, without requiring periodic visual inspection, water analysis or manual operation.

Abstract: Broadly, the present invention takes advantage of the ability of self-protonated sulfonated polyaniline (SPAN) to sense and/or modulate pH of a medium in the vicinity of a SPAN electrode. Accordingly, one aspect of the present invention is directed to a method for sensing pH of a medium in the vicinity of a sensing electrode wherein a SPAN electrode and a counter-electrode are placed in a medium and an indicia of said SAN correlative with the pH of said medium is monitored. As another aspect of the present invention, the pH of a medium in the vicinity of a sensing electrode is modulated by placing a SPAN electrode in the medium and applying a voltage to the electrode to controllably emit or absorb protons from said electrode to modulate the pH of the medium in the vicinity of the electrode. As a further aspect of the present invention, the activity/state of a biosensor/catalyst is sensed for the activity/state correlative with pH.

Abstract: A removable gelatinized calibration member is provided for use in storing or calibrating an ion concentration measuring device having measuring electrodes located in a concave measuring portion. The gelatinized calibration member is provided in the same shape as the concave measuring portion so that it may be removably placed onto the measuring device electrodes. The gelatinized calibration member may be a discrete pad or it may be provided in a rod-like configuration that can be moved in and out of a cylindrical housing.

Abstract: A method for determining the pH of liquids by a pH difference measurement of a solution under test and a reference solution and an apparatus for determining the pH of liquids is provided which can determine the pH with a precision equal to or better than 0.001 pH. The method and apparatus are especially useful for determining the pH and development speed of developers for positive photoresists.

Abstract: An apparatus for the simultaneous measurement of a plurality of ionic concentrations can utilize a test station having a common support sheet for supporting a plurality of ion selective electrodes, reference electrode and pH responsive electrode. Simultaneous measurements can be taken at the same time from a single sample and the pH reference electrode can validate the operative range of an ion selective electrode.

Abstract: A swimming pool water analyzer has a housing providing a coulometric titration chamber, a chlorine concentration measuring chamber, a chamber for measuring pH, and conduits connecting the several chambers, the reservoir and a discharge outlet. One or more pumps move fluid through the conduits and chambers to the discharge outlet. Electrodes in each of the chambers are connected to electrical circuitry, and a power supply is provided. A microprocessor receives and analyzes signals indicative of the activity at the electrodes and provides outputs representing values for the chemistry of the sample determined as a result of such analysis of the signals.

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: Self-assembly of a chemically insensitive redox material, such as ferrocenyl thiol, and a chemically sensitive redox material, such as a quinone thiol, onto microelectrodes forms the basis for a two-terminal, voltammetric microsensor having reference and sensor functions on the same electrode. Detection is based on measuring the potential difference of current peaks for oxidation and reduction of the reference (ferrocene) and indicator (quinone) in aqueous electrolyte in a two-terminal, linear sweep voltammogram using a counterelectrode of relatively large surface area. Use of microelectrodes modified with monolayer coverages of reference and indicator molecules minimizes the size of the counterelectrode and the perturbation of the solution interrogated. Key advantages are that the sensor requires no separate reference electrode and the sensor functions as long as current peaks can be located for reference and indicator molecules.