Abstract: A glucose monitoring system continuously measures the glucose concentration in a patient's blood, provides an indication of the rate of change of such concentration, and determines whether the measured concentration and rate of change are within certain preset limits. If not, an audible and/or visual alarm signal is generated. The glucose monitoring system includes a glucose sensor adapted to be inserted into the venous system of the patient, where it responds to blood glucose and produces sensor signals related to the glucose concentration. The sensor signals are delivered through a suitable interconnect cable to a glucose monitor. In one embodiment, the interconnect cable includes a contactless connector that electrically isolates the glucose sensor from the monitor, and reduces the number of conductors required to interface with a plurality of sensors. The glucose monitor interprets the sensor signals by applying a previously determined calibration to quantitatively determine the blood glucose value.

Abstract: A biosensor for measuring gas-phase organic chemicals rapidly and accurately. The biosensor includes a thick film electrochemical device having an insulating substrate, electrodes formed on the substrate, connecting pads for the electrodes and an insulating layer, and a responsive membrane formed on the electrode portion of the electrochemical device. The responsive membrane is provided with a moisture-absorbing gel layer in which an enzyme for reacting with the gas-phase organic chemical is immobilized.

Abstract: The biosensor of this invention can quantify a substrate in a sample liquid by electrochemically measuring the amount of an electron acceptor that has been reduced by electrons generated in a reaction between the substrate and an oxidoreductase. The biosensor has an electrically insulating substrate and an electrode system formed on the substrate including a working electrode, a counter electrode and a third electrode used for detecting a liquid junction. The third electrode can be used merely for detecting a liquid junction, or can be used as both a reference electrode and a liquid junction detecting electrode.

Abstract: A low cost room temperature electrochemical gas sensor with humidity compensation for sensing CO, alcohol vapors and other toxic analyte gases has a solid protonic conductive membrane with a low bulk ionic resistance. A sensing electrode and a counter electrode, optionally a counter electrode and a reference electrode, which are separated by the membrane, can be made of mixed protonic-electronic conductors, or can be made of a thin electrically conducting film such as platinum. A reservoir of water maintain the solid protonic conductive membrane at constant 100 percent relative humidity to compensate for ambient humidity changes. Embodiments of the inventive sensor also include an electrochemical analyte gas pump to transport the analyte gas away from the counter electrode side of the sensor.

Abstract: A device for batch injection stripping voltammetric analysis of metal traces, of very high sensitivity. This sensitivity extends down to about 0.03 to 0.3 ppb for certain metals. The microanalysis can be carried out at a high rate and in addition to the high sensitivity is characterized by accuracy and high reproducibility. One of the main features is a novel microcell with a rotating working electrode of the mercury coated graphite type.

Abstract: A photo-ablation technique is used to create apertures (4) in a layer (2) of electrically insulating material and allow electrically conducting material (3) exposed through the apertures to create a microelectrode. The microelectrode can be used for assay methods and in an assay unit.

Abstract: In this carbon monoxide sensor, particularly for measuring carbon monoxide in flue gases, which must be operated in a controlled-potential bias circuit and which comprises a working electrode, a counter electrode, and a reference electrode, all of platinum black, as well as an electrolyte connected with these three electrodes, the hydrogen cross-sensitivity is drastically reduced by providing two layers enriched by mercury and/or mercury ions, one on a surface of the working electrode and one of a surface of the reference electrode. These two electrodes are treated with mercury or a mercury compound before or after incorporation into the sensor.

Abstract: A compact electrochemical cell utilized for the detection of numerous toxic gases. The cell includes working and counter electrodes, surrounded by a liquid electrolyte, all of which is enclosed behind a gas permeable, hydrophobic membrane. The working electrode may be a single electrode or may be composed of multiple glassy carbon electrodes arranged in a planar electrode array. The counter electrode is either spatially separated from the array or comprises one or more electrodes in the array. The electrolyte composition varies with the type of gas to be detected and can be aqueous, partially aqueous, or substantially non-aqueous. The electrolyte includes an alkali metal halide. A fixed potential applied between the working and counter electrodes is sufficient to initiate electrochemical reactions in the presence of the gas to be detected without interfering reactions of the electrolyte or air.

Abstract: To avoid a reduction of the conductivity in iontophoresis due to the electrical decomposition and the changes in chemical properties of the electrodes themselves, covering by an electrical insulator, and to prevent a drop in the transport rate due to ions freed from the electrode. Provision is made of an electrode structure provided integrally with a reversible electrode and an auxiliary electrode for regeneration of the same and a regeneration current conducting means for conducting a current for regeneration of the reversible electrode when the therapeutic current is off, or the invention is comprised of a reversible electrode and an ion exchange membrane difficult for ions freed from that electrode to penetrate.

Abstract: A method and apparatus provide a system for measuring a measurable component in a sample. A sample is introduced into a chamber. A permeable membrane to the measurable component allows the component to pass into a second chamber. In the second chamber the component is measured directly or reacted in the presence of an enzyme to generate a detectable product detected by a detector therein. The second chamber is then flushed. The second chamber is only of a size sufficient to contain enough liquid to wet the detector therein.

Abstract: The invention relates to the amperometric detection of nitrite ions and nitrogen monoxide by electrocatalytic reduction by means of electrodes (15) modified by an electronically conductive polymer film such as poly-(N-methyl pyrrole) doped by mixed heteropolyanions of formulas:[M.sup.III X.sup.1 W.sub.11 O.sub.39 (H.sub.2 O)].sup.n- or[M.sup.III X.sub.2.sup.2 W.sub.17 O.sub.61 (H.sub.2 O)].sup.7-in which M represents Fe, Rh, Al, Ga, In or Tl,X.sup.1 represents P or As and n is equal to 4,X.sup.1 represents Si or Ge and n is equal to 5, orX.sup.1 represents B and n is equal to 6, andX.sup.2 represents P or As.It also relates to the films and modified electrodes used.

Abstract: A flow-through cell has a working electrode, an auxiliary electrode, a reference electrode, and a channel. The working electrode is a mercury drop electrode. The channel has a cross-sectional area of less than 1 mm.sup.2 in the region of the working electrode. The mercury drop is situated in the channel.

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 process for detecting nitrotoluenes, particularly trinitrotoluene, dinitrotoluene and derivatives of nitrotoluenes in soils, liquids and gases is proposed and a voltage is applied to an electrode which is in contact with an electrolytic solution having the substance to be tested, the voltage being reduced for producing a reduction reaction and increased for producing an oxidation reaction and the current intensity of at least a residual current and an anodic current maximum occurring is determined, particularly as a function of the voltage applied.

Abstract: An electrochemical cell for measuring concentrations of metal ions comprises a sampling enclosure including a working electrode, a reference electrode, and a counter electrode. Ports are provided in the sampling enclosure for the introduction and removal of a liquid sample, an auxiliary reagent, and a standard solution. A stirring mechanism maintains a uniform composition of the liquid sample during operation of the cell. The electrochemical cell is operated by introducing the liquid sample into the sampling enclosure, applying a plating voltage between the working electrode and the counter electrode, and measuring the voltage response of the working electrode when the applied voltage is removed. The concentration of metal ions is then calculated from the voltage response. A standard solution is added to the liquid sample, after which the measurement is repeated to calculate the concentration of metal ions relative to the standard solution.

Abstract: A metal-insulator-semiconductor diode sensor having a Pt/Ir alloy and/or a Pt/Sn alloy electrode is sensitive to and can detect ethylene. An array of metal-insulator-semiconductor diode sensors having varying sensitivity responses can indicate a fault in an electrical transformer by the detection of at least one of the key fault gases CO, H.sub.2, C.sub.2 H.sub.2 and C.sub.2 H.sub.4.

Abstract: The biosensor of this invention can quantify a substrate in a sample liquid by electrochemically measuring the amount of an electron acceptor that has been reduced by electrons generated in a reaction between the substrate and an oxidoreductase. The biosensor has an electrically insulating substrate and an electrode system formed on the substrate including a working electrode, a counter electrode and a third electrode used for detecting a liquid junction. The third electrode can be used merely for detecting a liquid junction, or can be used as both a reference electrode and a liquid junction detecting electrode.

Abstract: A thin film solid state amperometric detector for nitric oxide is provided based upon a mobile cation electrolyte that selectively transmits nitrosonium cations (NO*) therethrough. The presently most preferred embodiment employs NO-.beta.-alumina as the mobile cation electrolyte. The electrodes of the detector are preferably arranged in a bipotentiostat arrangement. The first and second working electrodes share a common reference electrode and a common counter electrode, which are positioned such that the potentials of the first and second working electrodes can be independently controlled. The first working electrode is exposed to a fluid (liquid or gaseous), whereas the second working electrode is normally isolated from the fluid. The first working electrode is set at a potential capable of oxidizing NO to NO+, the NO+ moves through the mobile cation solid electrolyte to the second electrode, and the second working electrode is set at a potential capable of reducing the NO+ back to NO.

Abstract: The method of electrochemical determination of oxygen partial pressure in ionic melts includes providing a metal/metal oxide reference electrode consisting of an electrode body made of a metal selected from the group consisting of Mo, W, Hf, Nb and Ta and alloys thereof and a layer of an oxide of that metal on the electrode body; immersing a pure platinum electrode and the metal/metal oxide reference electrode in a glass melt; measuring a potential across the metal/metal oxide reference electrode and the pure platinum electrode immersed in the glass melt to obtain a measured potential characteristic of the oxygen partial pressure in the glass melt; obtaining a calibration curve relating the potential across said reference electrode and the pure platinum electrode to the oxygen partial pressure in the glass melt as a function of temperature; and obtaining the oxygen partial pressure in the glass melt from the measured potential and the calibration curve.

Abstract: An ion concentration measuring apparatus for measuring the concentration of a measuring ion in a sample solution containing the measuring ion and an interfering ion having the same ionic charge number as that of the measuring ion. This apparatus comprises a first ion-selective electrode for generating a potential in response to the measuring ion, and a second ion-selective electrode in response to the interfering ion. The first ion-selective electrode is brought about in contact with a first, second and third standard solutions, each containing known concentrations of ions. A selectivity coefficient of the ion-selective electrode is calculated on the basis of the output potential of the first ion-selective electrode. The first and second ion-selective electrodes are brought about in contact with the sample solution.

Abstract: A biosensor for quantification of a specific component contained in various biological samples comprises an electrically insulating base plate, an electrode system including a working electrode and a counter electrode which are provided on the electrically insulating base plate, a reaction layer formed on the electrode system including at least an oxido-reductase, and an enclosure member having a hollow space constituting a sample supplying channel on the electrically insulating base plate, wherein substantially the whole of the reaction layer is exposed to the hollow space.

Abstract: A low cost room temperature electrochemical gas sensor for sensing CO and other toxic analyte gases has a solid protonic conductive membrane with a low bulk ionic resistance. A sensing electrode and a count counter electrode, which are separated by the membrane, can be made of mixed protonic-electronic conductors. Embodiments of the inventive sensor also include an electrochemical analyte gas pump to transport the analyte gas away from the counter electrode side of the sensor. Analyte gas pumps for the inventive sensor include dual pumping electrodes situated on opposite sides of the membrane, and include a means for applying a DC power across the membrane to the sensing and counter electrodes. Another embodiment of the inventive sensor has first and second solid protonic conductive membranes, one of which has a sensing electrode and a counter electrode separated by the first membrane, and the other of which has dual pumping electrodes situated on opposite sides of the second membrane.

Abstract: The miniaturized oxygen electrode having a small size exceeding the limit of miniaturization of the prior art electrode comprises an insulating substrate 21, 31 and, provided thereon, a pair of electrode patterns 22, 23 each comprising an active section 22A, 23A, a terminal section 22C, 23C for external connection, and a lead wire portion 22B, 23B for the connection thereof, the active sections 22A, 23A being mutually connected through an electrolyte-containing material 24, the electrolyte-containing material 24 being covered with an oxygen-permeable membrane 28, the lead wire portion 22B of at least one 22 of the electrode patterns extending below the active section 23A of at least one of other electrode patterns, 23, with an insulating layer 29 intervening between the lead wire portion 22B and the active section 23A.

Abstract: A biosensor for measuring alcohol concentration includes an insulating substrate and an amperometric device formed on the insulation substrate, having a plurality of conductive lines and connective pads and a plurality of electrodes. An enzyme immobilized layer is formed on one of the plurality of electrodes of the amperometric device and an enzyme paste is printed on the amperometric device. An outer membrane is formed on the substrate having the plurality of electrodes for forming an electrode system and an insulating membrane is formed on the substrate, except on the outer membrane.

Abstract: The present invention relates to a system for detecting, in a reliable, precise and highly sensitive manner, biochemical agents such as enzymes that catalyze a redox potential change. One electrode is used to measure redox potential changes in an aqueous electrolyte containing the biochemical agents. Another electrode is used to deliver a feedback current to the electrolyte in response to measured Changes in electrolyte redox potential. The amount of feedback current or charge delivered through the electrode to the electrolyte is sufficient in magnitude to maintain a constant redox potential. Quantitation of the amount of feedback current or charge necessary to maintain the constant redox potential may then be used to determine the amount of biochemical agents present. Alternatively, the redox potential need not be kept constant, but instead may be allowed to reach a new steady-state.

Abstract: The present invention provides electrochemical sensors for the detection of nitric oxide comprising a housing in which is disposed a working electrode, a reference electrode and a counter electrode. The electrochemically active surface of the working electrode preferably comprises RuO.sub.2. The nitric oxide electrochemical sensors of the present invention are capable of resolving nitric oxide concentrations at least as low as approximately 0.1 ppm and are well suited for use in medical environments because of their insensitivity to many other gases commonly used in medical environments.

Abstract: An apparatus and method of electrochemically determining an oxygen concentration with an oxygen sensor that includes a working electrode. The working electrode has a potential profile that includes a first potential step (a first measuring potential), a second potential step (a second measuring potential) and a third potential step. A measuring period is provided at the first and second measuring potentials. The currents flowing at the first and second measuring potentials are calculated and integrated over time. One of the two measuring potentials may be varied, depending on the difference between the two integrals of the currents flowing at the first and second measuring potentials, until the two integrals equal 0. An oxygen concentration is then determined from the value of a potential which thereby results.

Abstract: A voltage applying method for a hydrogen type enzyme electrode in a chemical sensor and using a pair of working electrodes, a reference electrode and a counter electrode includes detecting a contact of a test specimen with the enzyme electrode; keeping a potential applied to the working electrodes at a first potential of substantially zero for a first preset time; applying a second potential that is higher than a hydrogen peroxide detect potential to the working electrodes for a second preset time; dropping the second potential to a third potential below zero potential; and sweeping from the first potential to a fourth potential higher than said hydrogen peroxide detect potential at a fixed rate. Other variations of the method are disclosed.

Abstract: An electrochemical sensor cartridge with at least three reservoir cells, the floor of each cell in leakproof contact with the surface of an electrode assembly whose conductivity is affected by the presence of an analyte in that cell.

Abstract: An improved mercury electrode for electrochemical analysis is formed by a small diameter thread of liquid mercury contained within an inert tube which, at one point along its length, has an short, fixed length of thin walled tubular semipermeable membrane surrounding and forming the electrodes' active surface in order to prevent or reduce fouling of the surface while allowing the mercury thread to be advanced through the membrane to expose a fresh active surface whenever desired.

Abstract: On the bottom face of a measurement section, measurement electrodes and a reference electrode are formed and a solution supply pipe is opened. Then, if a predetermined electrolytic solution is supplied from the solution supply pipe, the electrolytic solution can be held on an electrolytic solution holding surface on the lower end of the measurement section, utilizing the with surface tension thereof for providing a gas reception portion. Since the electrolytic solution is exposed directly to the air, substances in a vapor phase (particularly, odor substances) are diffused into the electrolytic solution, causing an electric state to change. The substances in the vapor phase can be detected by detecting the electric state change. The electrolytic solution held on the lower face of the measurement section can be updated by further supplying more electrolytic solution.

Abstract: The invention concerns a novel electrochemical sensor with which to measure gas concentrations and comprising a measuring electrode and an associated electrode containing a carbonaceous material with a specific surface of at least 40 m.sup.2 /g and with electrochemically active surface compounds which can be reversibly oxidized/reduced.

Abstract: A gas sensor including an electrochemical sensor cell which has a anion-eange solid polymer electrolyte membrane with three attached electrodes is provided. The sensor cell contains no liquid electrolyte and is operated in the potentiostatic as well as the potentiodynamic modes to detect alkaline reactive gases, including vapors, such as hydrazines and derivatives thereof and ammonia. These sensor cells together with electronic circuitry, a pump and a power supply, fit into a compact, pocket-sized container to define the gas sensor of the invention which can detect traces of the above gases including 10 ppb of hydrazine and its derivatives and 10 ppm of ammonia. The invention includes the above gas sensor and the methods of operating same.

Abstract: A probe is disclosed for use with a dissolved gas meter, which is capable of measuring the concentration of dissolved gas in a fluid by measuring the permeation of gas through a membrane into an electrolyte solution. The probe includes an inner member, preferably tubular, disposed inside an outer member, preferably tubular, each tubular member having an open top end. Preferably, the inner tubular member and the outer tubular member are coaxially located such that an annular space is formed between the inner and outer tubular member. The probe further includes a plurality of electrodes operably connected inside the probe to the meter. A counter electrode extends into the central chamber of the inner tubular member, along the central axis. A working electrode is wrapped around the outer tubular member. A reference electrode is wrapped around the inner tubular member.

Abstract: An electrochemical detection cell (320), which is usable either for potentiometric or electrolytic conductivity detection, has a capillary (305), which controls electrolyte flow. A gas stream containing detectable substances is input through a non-wettable plastic capillary (306). A reaction zone (310) through which both gas and liquid flow is internally wettable. Reference electrode (309) and either electrode (311) or (312) may be used for potentiometric detection. Sensor electrodes (311) and (312), both in the reaction zone, are used for conductivity detection. The electrolyte is fed through the capillary (305) gravimetrically from a reservoir, and the gas stream is supplied by a pyrolysis furnace. The mechanism of ionization in the gas phase ionization detector (GPELCD) is described.

Abstract: The present invention provides a diagnostic flow cell for determining the presence or amount of an analyte which may be contained in a test sample. The flow cell comprises a spacing layer having a longitudinal void disposed between a pair of opposed substrates. The spacing layer and the opposed substrates define a flow channel wherein reagent means can be immobilized. When the immobilized reagent means is contacted with an analyte, the reagent means can produce an electrically, optically, or electrically and optically detectable response to the analyte. Hence, the reagent means that is immobilized within the flow channel can comprise (i) a counter electrode, a reference electrode and a working electrode, (ii) an optically sensitive dye or (iii) a counter electrode, a reference electrode and a working electrode and an optically sensitive dye.

Abstract: A sensitive and rapid electrochemical sensor monitors motor oil deterioration, particularly antioxidation property, by determining the antioxidant and antiwear agent level remaining in an oil formulation. The electrochemical sensor is a two- or three-electrode electrochemical cell having a conductive electrolyte liquid or gel-like interphase over the electrode surfaces. The degree of deterioration of a motor oil in service is monitored by measurements of antioxidation or antiwear capacity of the oil. The electrochemical sensor can be used for monitoring other lubricants and hydrocarbons which contain electroactive additives. The electrochemical sensor allows measurements to be performed in-situ, without any chemical or physical pretreatment of the oil.

Abstract: An amperometric sensor detects acidic and alkaline gases utilizing a first pH-dependent reversible redox system on a measuring electrode 4. A reduction current occurs between the measuring electrode 4 and a counter electrode 6 for a constant potential and is used as a measurement variable of the concentration of the gas to be detected. In addition, a reference electrode 5 is disposed in an electrolyte 7 together with the measuring electrode 4 and the counter electrode 6. The gas to be detected penetrates through the permeable membrane 2 and is dissolved while being dissociated. The amperometric sensor is improved with respect to its permanent stability. This is provided in that the first pH-dependent redox system is coupled to a second redox system and the redox potential of the second redox system is so selected that the reaction product is chemically regenerated again to the educt via the second redox system. The reaction product is electrochemically formed at constant potential by the first redox system.

Abstract: A biosensor of the present invention is provided with an insulating base plate, an electrode system mainly consisting of a working electrode and a counter electrode formed on the insulating base plate, and a reaction layer on the electrode system. The counter electrode is partially a circular arc. A manufacturing method of the biosensor of the present invention is comprised of a step to form a base by arranging leads, an electrode system, and an insulating layer on an insulating base plate, and a step to form a reaction layer mainly composed of an enzyme on the electrode system. Since the counter electrode is partially in the shape of a circular arc, the reaction layer is easily formed and prevented from delaminating, whereby the measuring accuracy, preservative properties and reliability of the biosensor are improved. The present invention enables highly efficient biosensors to be mass produced at low cost.

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: An electrolyte such as a saturated picric acid solution in a cell for measuring electrochemical polarization is placed in contact with an alloy steel such as a CrMoV steel which has been subjected to a high-temperature and stress-applied condition, and a potential is swept between the CrMoV steel and a salt bridge in the cell, whereby the Mo-rich carbide M.sub.6 C undergoes a dissolution reaction at a potential near a specified value and this reaction is visible as the secondary anode peak current, or the second appearance of peak current on the waveform of electric polarization. Since the secondary anode peak current is closely related to the amount of M.sub.6 C precipitation, the progress of degradation in the CrMoV steel can be evaluated by a simple method with good precision.

Abstract: A process for the quantitative determination of oxidizing and reducing substances is described, also mixed with chemically similarly reacting substances, particularly peracetic acid mixed with further substances such as hydrogen peroxide (H.sub.2 O.sub.2) and/or acetic acid by means of per se known potentiostatic amperometry, in which the determination takes place with a test electrode voltage, which, independently of the prevailing reaction mechanism, is below the diffusion limiting current range between the no-load voltage and the flex point of the current density-voltage curve. The peracetic acid determination takes place at a current density of <5%, preferably <1% of the limiting current density.

Abstract: Photoresponsive devices including a photoresponsive electrode are provided, and methods for their use to measure changes in environment at a site at or about the surface of the photoresponsive device. By employing a source of light for irradiating a site on the surface and means for biasing the photoresponsive electrode in relation to a counterelectrode, a variation in electrical signal can be related to a change in a medium in photoresponsive modulation relationship to the photoresponsive electrode surface.

Abstract: A procedure and an apparatus to determine the concentration of dissolved ammonia. A polypyrrole electrode (2), a reference electrode (1) and an auxiliary electrode (5) are placed in the liquid to be analyzed and the concentration of ammonia dissolved in the liquid is determined by a potential applied between the polypyrrole electrode (2) and the reference electrode (1) and of the current flowing between the polypyrrole electrode (2) and the auxiliary electrode (5). A polypyrrole layer (4) is formed on a platinum substrate (3).

Abstract: A solid state, multi-use electrochemical sensor having an electrically nonconductive substrate, a working electrode, and a semi-permeable membrane covering the working electrode. The working electrode includes an electrically conductive material adhered to a portion of the substrate. A first portion of the conductive material is covered with an electrically insulating dielectric coating, and a second portion of the conductive material is covered with an active layer. The active layer includes a catalytically active quantity of an enzyme carried by platinized carbon powder particles, which are distributed throughout the active layer. A sensor package for incorporating a sensor is provided.

Abstract: The invention provides a method and apparatus for measuring the quality of a coating on a plate. The invention uses a method of measuring the impedance of a coating on a plate, which uses the steps of placing the coating on a plate in a chamber, and then placing a counter electrode in the chamber so that the coating lies between the plate and the counter electrode. A reference electrode is placed in the chamber so that the coating lies between the reference electrode and the plate, and the chamber is filled with a fluid with an ionic substrate. A potentiostat induces a voltage between the plate and the reference electrode, and impedance of the coating is measured to determine the quality of the coating.

Abstract: A solid state electrochemical cell is provided for performing electrocheml measurements on a solid electrolyte at high temperatures. The solid state electrochemical cell includes a noble metal working electrode, a lithium alloy reference electrode, and counter electrode, and a solid solution of lithium germanium oxide and lithium vanadium oxide as the solid electrolyte.

Abstract: This invention relates to a sensor for the direct and continuous measurement of the electrochemical properties of compounds in a high resistivity liquid. The sensor has a housing which includes a porous hydrophilic membrane which may be made of a ceramic, and contains an electrolytic solution. The membrane permits the passage of a portion of the electrolytic solution into the pores thereby facilitating the formation of an interface between the electrolytic solution and the high resistivity liquid and allowing extraction of the compounds in the high resistivity liquid into the electrolytic solution. A porous sensing electrode is positioned directly on the membrane for detecting and measuring the concentration of the compounds extracted from the high resistivity fluid.

Abstract: Water quality sensor apparatus comprising a substrate on which a plurality of sensors are supported in spaced apart relationship, each sensor being responsive to a different water characteristic and each sensor comprising a sensor region which, in use, is arranged to be contiguous with water the characteristics of which are to be sensed, which sensor regions are electrically connected to connector means via conductors supported on the substrate, the conductors and the connector means being arranged to be non-contiguous with the water in use of the apparatus.