Abstract: Batch injection analysis comprises apparatus and method for injecting and transporting analytes toward a detector immersed in a confined, inert electrolyte. Passage of the analyte over the detector surface provides measurement of sample concentrations. Detectors normally comprise selective electrodes, such as biologically or chemically modified surfaces, ion-selective probes, optical or thermal devices, thus eliminating conduits, valves, and pumps.

Abstract: The present invention is addressed to an electrode for evaluating electrochemical potentials which has a robust structure particularly suiting it for employment within the rigorous environment of the reactor core of a nuclear power facility. The electrode of the present invention is comprised of five major segments: a metal cap electrode, an elongate annular metal jacket, an alumina retainer (i.e. an insulator), an annular metal transition sleeve, and a positioning and signal transfer assembly. The metal cap electrode has a tip and annulus extending therefrom formed from sidewalls having an interior surface. The elongate annular metal jacket has an annular retainer securing mouth at one end and an outlet at its opposite end. The alumina retainer has a recessed cap securing portion nestably secured to a portion of said cap electrode interior sidewall surface, and an oppositely-disposed recessed jacket securing portion nestably secured to the interior of said annular jacket retainer securing mouth.

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: A film-coated sensor is formed by providing an electrically conductive substrate (2), which has a sectional area of less than 10.sup.-5 cm.sup.2, connected to a lead wire (5) at one end of an insulative capillary (1) and inscribed in the capillary (1), and providing a coating film (7) at another end, which is open, of the capillary (1) by an electrolytic polymerization process.The film-coated sensor obtained has a surface which is uniform, the film coating is easy to control, and since the sensor is not readily susceptible to flow of a specimen fluid, there is little drift and response is quick. Owing to its small size, the sensor is capable of measuring very small samples and of performing measurement upon being directly inserted into a living body or tissue.The sensor can be used also as an enzyme sensor by coating the surface of the film-coated sensor with a fixing enzyme film.

Abstract: An improved ion-selective electrode assembly and method of preparing the same includes providing a substrate of an insulating material which has a laminated polyethylene terephthalate film layer over an electrically conductive layer. A series of adhering layers is applied over the film layer, with the layer farthest from the substrate being a deoximation silicone room temperature vulcanizing adhesive. Gelatinized internal liquid is positioned in an aperture over the electrically conductive layer, and an ion-responsive glass sheet seals the assembly.

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: The invention relates to a reference electrode for chemical sensors based on ion-selective field-effect transistors (CHEMFETs) in an electrolyte/insulator/semiconductor system. The reference electrode is essentially composed of a polyglutamate-coated insulator/semiconductor substrate or of a polyglutamate-coated phthalocyaninato-polysiloxane polymer film applied to an insulator/semiconductor substrate.

Abstract: Phosphate ion-sensitive composition and ion-selective electrode are disclosed incorporating an ionophore having the formula:R.sub.1 --X (a)orX--Z--X (b)wherein R.sub.1 is H or a hydrophobic substituent, Z is a spacing unit and X is represented by the formula: ##STR1## wherein n=0 or 1 and R.sub.2 and R'.sub.2 are independently selected from the group consisting of CH.sub.2, C(O) or C(S).

Abstract: A heavy metal-free composition and its method of use in an ion selective electrode-based assay are disclosed. The heavy metal-free composition includes a borate compound and an alkalinity adjusting compound, and is used to dilute a test sample; buffer the test sample; and substantially reduce the effects of interferents present in the test sample on the ion selective electrode-based assay. The heavy metal-free composition and its method of use are especially useful in an ion selective electrode-based assay for carbonate ion concentration in a test sample, like blood serum, blood plasma, urine or cerebrospinal fluid.

Abstract: In order to simplify the performance of serial measurements by means of a measuring device for determining chemical parameters of an aqueous sample, with at least one symmetrical, ion-sensitive membrane being located between the sample and an electrolytic medium and the sample and the electrolytic medium being in contact with reference electrodes connected to an evaluation unit, a measuring element is provided which can be inserted into a measuring device and which has a sample chamber connected with a reference chamber via a bore. At least one measuring chamber is provided, which is separated from the sample chamber by a symmetrical, ion-sensitive membrane. The reference chamber and all measuring chambers contain electrolytic media into which are dipped the reference electrodes located in the measuring device.

Abstract: A portion of a board (1) on which copper wiring is printed is provided with a carbon coating, the board (1) and lead wires (2) are joined by solder (3), the portion having the solder (3) is insulated with a silicone resin (4), and the carbon-coated printed wiring portion (10a) is successively coated with a redox layer (11) obtained by electro-oxidation of 2,6 xylenol and an ion-selective layer (12), thereby forming an ion sensor (20).Since the ion sensor can be formed on a printed wiring board, various devices which include an ion sensor can readily be fabricated on a board.

Abstract: The present invention includes an ion diffusion junction in an electrochemical cell. The junction includes a polymer matrix that is impermeable to the sample solution. A plurality of inclusions are disposed within the junction matrix and oriented to form continuous hydrolytic pathways extending between the sample solution and the reference electrolyte such that ion diffusion occurs along the hydrolytic pathways.

Abstract: A sample of a body fluid, such as blood, is collected in a cartridge having a sample chamber for storing the sample and one or more calibration chambers, each for storing a respective calibration fluid. The fluid sample is drawn ino the sample chamber by placing the sample chamber in fluid communication with a needle inserted into the fluid sample and applying a vacuum to the chamber using either a syringe or internal vacuum. A body fluid sample may also be drawn into the sample chamber from a syringe or capillary tube containing the fluid sample. The cartridge may be either planar or cylindrical. The chambers of a cylindrical cartridge may be either elongated voids symmetrically positioned about the longitudinal axis of the cartridge or axially spaced annular voids.

Abstract: An electrochemical cell is formed by immersing an electrochemical ion sensor and a reference electrode into a solution of interest, the electrochemical ion sensor exhibiting ion selectivity with respect to an ion of interest and having a high electrode resistance. A current which flows through the electrochemical cell is measured while the potential of the electrochemical ion sensor is held to a constant potential with respect to the reference electrode. The current so obtained are proportional to the logarithm value of the concentration of the ion.

Abstract: An FET sensor apparatus comprising a sensor, a base member, and a support. The sensor comprises a semiconductor substrate having a predetermined crystal plane, a field-effect transistor formed on the semiconductor substrate, and a gate portion arranged on at least one of the major surfaces of the semiconductor substrate. The base member has a through hole in which the field-effect transistor is fitted. The support supports the sensor in the through hole in watertight fashion, with said gate portion exposed through an end of the hole.

Abstract: Apparatus for measuring electrolyte concentrations in fluid samples. The apparatus includes an ion selective electrode capable of generating a voltage differential having a magnitude related to the concentration of the corresponding electrolyte in the sample. A voltage to optical transducer circuit is provided to convert the voltage differentials to a digital code and then to an optical signal which is related to the concentration of the electrolytes. The optical signals are suitable for detection by conventional optical detector apparatus of assay instruments. A passive duplex transfer is utilized to simultaneously read one optical signal while transferring the next bit of the digital code. The duplex transfer configuration also makes novel use of the photodetection properties of an LED.

Abstract: An ion sensor of the type wherein a specific type of ion in an aqueous solution is measured by potential response. The sensor includes a conductor base, and a reversible redox polymer film formed directly on a surface of said conductor base. An ion carrier film is formed directly on a surface of said redox polymer film. The carrier film contains an ion carrier substance for allowing the specific type of ions to permeate from the aqueous solution to said polymer film.

Abstract: A calibration solution, which is used when measuring the ion concentration of solution under examination such as blood or other body fluids using a pH sensor or the like ion sensor with a solid electrode, is prepared by adding NaCl to a standard buffer solution and thus setting the ionic strength of the solution to be substantially identical with the ionic strength of solution under examination. A sensor calibration method is also disclosed, in which at least two reference calibration solutions having different pH values are prepared, the electromotive force of the sensor in these calibration solutions is measured by immersing the sensor in the solutions, and a calibration formula is produced from the electromotive force for the pH values of the reference calibration solutions. A predetermined amount of bicarbonate buffer solution is added to the calibration solution to maintain a substantially constant ionic strength of the solution, thus permitting simultaneous calibration of an ion sensor and a gas sensor.

Abstract: One of the fundamental limitations of voltammetric detectors in flow analysis is the problem of passivation or contamination of the working electrode. The present invention proposes a voltammetric detector based on the wall-jet principle which incorporates the concept of a replaceable working electrode. The voltammetric detector represents a significant improvement over existing detectors which are fully enclosed or sealed devices precluding easy replacement of the working electrode.The design of the present invention provides a detector where the top is fully open and where the solution volume is maintained by the outlet positioning. The other feature of the proposed detector is an optimised geometry that provides well defined wall-jet flow characteristics which is not provided in existing detectors.

Abstract: A liquid containing ions is introduced onto the surface of an electrode, gas is supplied so that the liquid is moved while being held between the gas and the electrode, an electric field is applied so that the ions are extracted from the liquid, and the extracted ions are detected.

Abstract: An ion-selective polymeric membrane for an electrochemical sensor for use in analytical chemistry, comprisinga) a supporting matrix e.g. of PVC, andb) an ionophore selected from calixarene or oxacalixarene derivatives of the formula IV ##STR1## wherein n+m=3-8;m=0-8;n=0-8;a, which may be the same or different on each aryl group, is 0 or 1;R.sup.2 is alkyl, aryl, alkaryl, alkoxy, alkoxyalkoxy, aryloxy, alkaryloxy, alicyclic, alkylthio, arylthio, alkarylthio, or a substituted derivative thereof;R.sup.3 is --H, alkyl or alkenyl;X is --OH or a group containing an acrylate or methacrylate functional group;provided that when X is --OH, n is at least 1/2(n+m);and provided that when m=0, n=4, a=0 and R.sup.3 is alkyl or allyl, R.sup.2 is not alkoxy having 4 or more carbon atoms in the alkyl group;and provided that when m=0, n=4, a=0 and R.sup.3 is t-butyl, R.sup.2 is not methoxy or ethoxy;or of the formula V ##STR2## wherein R.sup.

Abstract: Sodium ion selective compositions which comprise an ion carrier, a compound capable of solvating the ion carrier, and a supporting matrix are disclosed.The ion carriers of this invention are hemispherand compounds represented by the formula ##STR1## wherein R.sup.1, R.sup.2, R.sup.3, and R.sup.4 are independently hydrogen, alkyl, alkenyl, cycloalkyl, aryl or a heterocyclic group and R represents Z-decyl, Z-octyl, 3-octyl, and cyclohexyl methyl.

Abstract: A process for obtaining a multifunctional, ion-selective-membrane sensor is disclosed, which process comprises the following steps:a) preparation of a siloxanic prepolymer, followed by one or more deposition(s) of said siloxanic prepolymer on a device of MOS or ISFET type;b) preparation of a solution containing an ionophore, a monomer of a polymerisable olefin, 2,4-toluenediisocyanate and a dialcohol or a diamine or a glycol or a trialcohol or a triamine, which preparation is followed, after that said solution has been kept stirred for at least 48 hours at room temperature, by the deposition thereof on the siloxanic prepolymer, which deposition is carried out by means of a spinner;c) photochemical treatment in the presence of a photoinitiator by means of UV light, with a suitable mask being used, which allows the exposure to UV light to take place on one gate only;d) chemical washing of the sensor, by means of an organic solvent;e) thermal treatment ("thermal curing"), so as to complete the reactions of polym

Abstract: An apparatus and method for directly indicating the gold content of a metal object employs a receptacle or cell into which is deposited a small portion of an electrolyte solution. The solution preferably contains copper and iron ions, acetic acid and hydrogen peroxide. At the bottom of the cell is a first electrode preferably of pure gold in contact with the solution. The first electrode is electrically connected to an electronic measuring and indicating apparatus. The metal object to be tested is connected by a metal spring clip to the electronic apparatus and then a portion of the object is immersed in the solution so that it forms the second electrode of an electrochemical cell. The electronic apparatus measures the voltage generated in the electrochemical cell after the voltage has stabilized and indicates by indicating apparatus the gold content of the metal object.

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: An electrochemical detection system is described comprising in combination:(a) a multielement, microelectrode array detector containing means for acquiring a plurality of signals;(b) electronic means for receiving said signals and converting said signals into a readout or display providing information with respect to the nature and concentration of elements present in a solution being tested.Also described is the means of making the above described microelectrode detector.

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: A luminescent probe complex for measuring pH comprising, polypyridine ligands having ion dissociable substituents on their carbon rings and a transition metal ion selected from the elements of the VIII group of the periodic table.Also disclosed is a luminescent probe membrane for measuring pH wherein the probe complex is contained in a macromolecular membrane. Further disclosed is a device for measuring pH wherein the probe membrane is immobilized at the tip of an optical fiber.A method for measuring pH using the above are also disclosed. The present invention enables measurement of pH of microenvironments.

Abstract: An anion-selective electrode of the present invention comprises, as anion sensitive substance, a tetraalkyl type, quaternary phosphonium salt having four alkyl radicals, each having 8 to 24 carbon atoms; a combination of a tetraalkyl onium salt having four alkyl radicals each having 10 to 24 carbon atoms, and an onium salt having one alkyl radical with 1 to 20 carbon atoms and three alkyl radicals with the proviso that the number of carbon atoms contained in the three alkyl radicals each is larger than that contained in the one alkyl radical; or a tetraalkyl type, quaternary onium salt having an asymmetrical molecular structure. The anion-selective electrode has good properties including selectivity and measurement accuracy. An anion-selective, field effect transistor or a chemical analysis apparatus, provided with the anion-selective sensitive substance, is suitable for measuring an anion concentration with a high accuracy.

Abstract: The electromotive force of a standard liquid for correction is measured. Both before and after this measurement, the electromotive force of a reference liquid is measured at least once. A calibration curve is prepared based on the resultant data. The calibration curve is used to convert the electromotive force difference between a test liquid (the ion concentration of which is to be measured) and the reference liquid. Both before and after the measurement of the electromotive force of the test liquid, the electromotive force of the reference liquid is measured at least once. By so doing, the electromotive force difference between the test liquid and the reference liquid is obtained. The ion concentration of the test liquid can be detected accurately by plotting the electromotive force difference against the calibration curve.

Abstract: This invention relates to a semiconductor substrate having a porous surface nd to the amperometric receptor-based sensors formed with the substrate. More specifically, this invention pertains to the substrate in the form of a bipolar junction transistor having a porous hydrophilic surface directly on its base wherein the surface forms a support for an amperometric sensor. The invention also pertains to the methods of making and using the substrate and sensor.

Abstract: A metal/metal oxide electrode for determining chlorine in aqueous solutions comprises a metallic tantalum core on which there is non-porous tantalum suboxide.

Abstract: A calcium ion selective electrode having a sensitive membrane comprising an organic polymeric substance, a plasticizer and a calcium ion sensitive substance of neutral carrier type, wherein the dielectric constant of the plasticizer is 10 or less, thus remarkably improving the responsiveness and stability of the electrode.

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: Precalibrated, disposable electrochemical sensing devices can be constructed so as to utilize a housing shaped so as to internally include at least two separate half cells, one of which is capable of serving as a reference half cell and the other of which is capable of serving as a sensing half cell. The housing is shaped so as to include a top depression capable of being used as a container which is in communication with the interiors of the half cells. The depression is capable of holding for a sample to be analyzed using the device. The housing is preferably mounted on a board which is capable of being plugged into a female socket. This board carries electrodes which are connected to electrodes in the half cells.

Abstract: A safe failure ion selective combination electrode in which a signal unit provides a signal if combination electrode output falls outside a predetermined range.

Abstract: A sensor system for determining the pH or carbon dioxide concentration of a liquid medium comprising, in combination, a pH-insensitive fluorescent indicator and a PH-sensitive fluorescent indicator which act in concert or a single fluorescence indicator which emits fluorescent signals of different wavelengths in different carriers, which system(s) produce diverging signals, the ratio of which provides an accurate and stable determination of the parameter being measured. A method for determining pH and CO.sub.2 concentration is also disclosed.

Abstract: A flow cell comprises an examining liquid flow passage, a comparison liquid flow passage communicated with the examining liquid flow passage, plural ion selective electrode openings communicated with the examining liquid flow passage, and a comparison electrode opening communicated with the comparison liquid flow passage. The examining liquid flow passage is provided with linear inlet and outlet parts which are communicated at their one ends with each of the ion selective electrode openings, and curved parts each of which connects the linear outlet part which is communicated with the ion selective electrode opening to the linear inlet part which is communicated with the next ion selective electrode opening.

Abstract: An apparatus and method for directly indicating the gold content of a metal object employs a receptacle or cell into which is deposited a small portion of an electrolyte solution. The solution preferably contains copper and iron ions, acetic acid and hydrogen peroxide. At the bottom of the cell is a first electrode preferably of pure gold in contact with the solution. The first electrode is electrically connected to an electronic measuring and indicating apparatus. The metal object to be tested is connected by a metal spring clip to the electronic apparatus and then a portion of the object is immersed in the solution so that it forms the second electrode of an electrochemical cell. The electronic apparatus measures the voltage generated in the electrochemical cell after the voltage has stabilized and indicates by indicating apparatus the gold content of the metal object.

Abstract: An electroanalytical electrode assembly includes an electrically conductive working electrode having a body of electrolyte material thereupon and separated from the analytical environment by a hydrophobic membrane. The membrane has an electrical conductivity greater than the electrical conductivity of the remainder of the measuring circuit and is selectably permeable for a preselected and ionic species, so as to provide a stable membrane potential. Use of an assembly of this type allows for placement of a reference electrode external of the membrane.

Abstract: A chemical sensor includes a field effect-type transistor. An extended gate electrode is connected to a gate electrode of the transistor. A sensitive membrane is provided on at least a part of the extended gate electrode. The sensor also includes a reference electrode. Both the extended gate and reference electrodes are formed on a substrate different from the substrate on which the transistor is formed. Divided parts for the chemical sensor wherein the parts of the sensor except for the reference electrode are made independent are also disclosed and claimed. Sensors for simultaneously sensing a number of different chemical substances in a single sample are also disclosed and claimed.

Abstract: The sensor comprises a chip of a semiconductor material wherein a field-effect transistor is formed the drain and source regions whereof are provided on a first face of the chip, onto which an ion-selective membrane is applied which is coupled to said field-effect transistor.The membrane covers said first face of the chip completely, and terminals are provided in addition which comprise conductive elements applied to the other face of the chip and being connected to said drain and source regions by connections which extend through the chip.These connections are formed by a method providing for the formation in the chip of buried layers of semiconductor material.

Abstract: A reference electrode for generating a reference potential on an ion sensor is disclosed. The reference electrode has a lamination film covering a surface of an electrically conductive substrate and formed by alternately laminating silver halide thin films and hydrophobic resin thin films.

Abstract: A disposable cartridge for use in a clinical sensing arrangement interfaces electrically with a host instrument capable of responding to electrical signals generated by detector devices incorporated in the cartridge upon exposure to calibrant fluids and/or clinical fluids under examination. The cartridge includes a passage linking a reservoir of calibrant fluid to the detector devices and further linking the device to a closed container for fluid which has been conveyed past the devices. A fluid under test can be introducted into the cartridge through the passage wall at a location disposed between the reservoir and the detector devices.

Abstract: The surface of a gate insulating membrane of an ion-selective field-effect transistor (ISFET) (10) is coated with a carbon thin membrane (4), and the surface of the latter is coated with an electrolytic polmerization membrane (3) of 2,6 xylenol. The ISFET obtained exhibits hydrogen-ion selectivity, little drift, high stability and little response to light. If the surface of the electrolytic polmerization membrane (3) of 2,6 xylenol is coated with another ion-selective membrane or enzyme-active membrane, various ions and the concentration of a biological substrate can be measured.

Abstract: An apparatus for setting the ion concentration in an ionic water generator which separates drink water between alkaline ionic water and an acidic ionic water by applying a DC voltage between electrodes in an electrolytic cell which are partitioned by an ion-exchange membrane apparatus comprises a device for measuring voltage drop at a portion leading to the electrolytic cell which is caused when a reference voltage is applied, and a calculator for calculating voltage Vx which is applied to the electrolytic cell to adjust ion concentration to a desired value from a proportion k of the voltage drop which is calculated by application of the reference voltage to water to be examined relative to the reference voltage drop caused by application of the reference voltage to reference water and a set voltage Vn which corresponds to the desired ion concentration on the basis of the following equation:Vx=k.times.Vn.

Abstract: A chemically sensitive transducer for selectively determining a chemical property of a fluid and providing a measurement signal to an amplifying circuit. The transducer has a measuring electrode coupled to the amplifying circuit and provides a measurement signal to the amplifying circuit. A membrance covers the measuring electrode, this membrane being sensitive to a specified chemical property. A carrier plate, with first and second sides, has the measuring electrode arranged on its first side and the amplifying circuit on its second side. The carrier plate has a conductor extending between the first and second sides which electrically couples the measuring electrode and the amplifying circuit.

Abstract: An analyzng device comprises a plate holding table, a shifting mechanism for shifting the plate holding table, bar code reading sensors, and a detecting unit for detecting the signals based on the drops of the solutions in the plate set on the plate holding table located in the plate measurement position. When the data of the bar code read by the bar code reading sensor is not fit for a predetermined measurement condition, the plate holding table is shifted to the plate exhausting position. On the other hand, when the data of the bar code is fit for the predetermined measurement condition, the plate holding table is shifted to the solution pipetting position and when the pipetting of the solutions is finished, the plate holding table is further shifted to the mesurement position. When the concentration of substance in the test solution is completed by the detecting unit, the plate holding table is shifted to the plate exhausting position.

Abstract: An ion sensor is disclosed, together with the relevant process for preparing it, which contains a polymeric organic matrix, a ionophore, a device based on semiconductors of EMOS or ISFET (CHEMFET) type containing at its surface silicon oxide adhering to said polymeric organic matrix by means of a polysiloxanic matrix, characterized in that the polysiloxanic matrix is selected from the organosilanes of general formula ##STR1## wherein: R.sup.II, R.sup.III, R.sup.IV, which may be either equal to, or different from, one another, are alkyl or alkoxy groups containing from 1 to 10 carbon atoms,R.sup.I is equal to (CH.sub.2).sub.p X (CH.sub.2).sub.q wherein:X is CH.sub.2, or an either mono- or polycondensed aromatic group, or NH or O,p and g, which may be either equal to, or different from, one another, are integers which can have values comprised within the range of from 0 to 10, with value 0 being excluded when X is either NH or O,Y is --NH.sub.

Abstract: A device for measuring the activity of carbonate ions and hydrogen ions comprises a carbonate ion selective electrode pair and a hydrogen ion selective electrode pair. Each ion selective electrode comprises a metal layer, metal halide layer and ion selective layer superposed in this order. A porous bridge is disposed so as to achieve a liquid junction between the ion selective electrodes of each electrode pair.