Abstract: The present invention is a sensor formed over a subminiature through hole. Because of the small diameter of the through hole, the material that fills the through hole and the through hole itself have an essentially negligible effect on the sensor. Only a small amount of conductive material which fills each through hole is in contact with each associated electrode. Therefore, the purity of the electrode is not significantly altered by the conductive material coupled to the electrode. A relatively large number of sensors can be formed on the surface of the substrate within a relatively small fluid flowcell. Thus, more information can be attained using less blood. The sensors of the present invention are preferably disposed on an alumina substrate which is essentially impervious to aqueous electrolytes and blood over long periods of storage in potentially corrosive environments.

Abstract: Disclosed is a method and apparatus for electrolytically generating an acid or base eluent in an aqueous solution and for simultaneously suppressing conductivity of the eluent in an ion exchange bed after chromatographic separation in an ion chromatography system.

Abstract: A method and apparatus for generating an acid or base eluent in an aqueous stream solely from an ion exchange bed for liquid chromatography of anions or cations and for simultaneously suppressing conductivity of the eluent in the ion exchange bed after chromatographic separation. For a system in which a base is generated for the analysis of anions by ion chromatography, the method uses a bed of cation exchange material with first and second bed sections arranged in series.

Abstract: An apparatus for measuring ion concentration of a solution includes an ion sensitive field effect transistor (ISFET), a reference device, an ISFET control circuit, a memory, a measurement circuit and a diagnostic circuit. The ISFET has a drain, a source, an ion sensitive gate region and a plurality of device characteristics. The reference device is separated from the gate region by a sample solution. The ISFET control circuit is coupled to the ISFET and operates the ISFET at a drain-source voltage V.sub.DS and at n successive drain currents I.sub.Di and corresponding gate-source voltages V.sub.GSi, wherein i is an integer from 1 to n and n is an integer greater than 1. The memory stores the plurality of device characteristics and the n successive drain currents I.sub.Di and gate-source voltages V.sub.GSi. The measurement circuit measures ion concentration of the solution as a function of at least one of the n successive drain currents I.sub.Di and gate-source voltages V.sub.

Abstract: An amperometric sensor device comprising a working electrode, a reference/pseudo-reference electrode and a permselective membrane incorporating a charged organic species. The electrodes are in intimate contact with the membrane and are on a side of the membrane opposite to the side exposed to a fluid sample. The charged organic species provides a conducting path through the membrane between the electrodes.

Abstract: Electroanalysis of an electroactive, and especially ionized, species, in trace form, in a liquid sample, is by potentiometry with coulometric stripping (elution), and is by employing a working electrode in electrical contact with the sample. A practically exhaustive electrolysis, or a practically exhaustive complexing with adsorption, of the electroactive species, a main coulometric stripping and at least two poststripping cycles including a post-electrolysis step and a poststripping step are performed in succession. By a particular choice of the operating parameters and of the measured parameters it is possible to determine automatically the equivalent mean chemical current, for example for oxidation, competing with the current applied to the working electrode, during the stripping stage. This is done directly from the liquid sample which is being analyzed. As a result, the required concentration of the species is determined without previous calibration.

Abstract: A conductivity cell for use in determining ionic concentrations in the gap between two semiconductor substrates or wafers. The wafer gap conductivity cell is composed of two flat electrodes separated by a fixed gap. The electrodes are fabricated from wafers of the same type and dimensions used as semiconductor device substrates. All or a portion of the surfaces of the wafer electrodes are coated with a conductive material. The wafer gap conductivity cell is placed in a wafer cassette or other suitable wafer holder, whose other slots are filled with wafers which are to be cleaned or subjected to another fabrication process. The cell can be used to characterize the processes used during the fabrication of semiconductor devices and assist in investigating the effect on the processes of different process vessel designs.

Abstract: An electrochemical oxygen sensor comprises an impermeable substrate and a plurality of conductive layers applied thereto by thick film deposition. At least one conductive layer comprises an electrode and a conductor connected to the electrode. The electrode may have a covering layer of an ion exchange polymer.

Abstract: The invention relates to a method as well as to an electrochemical sensor for measuring the concentration of at least one predetermined gas in a gas mixture by means of an electrolyte provided with a first and a second surface-mounted electrode, which are exposed to the gas mixture together with the electrode connected to a voltage source, wherein the voltage source causes an electrical current flowing through the electrodes and electrolyte, which is dependent upon the ion concentration and is measured as an indicator of the gas concentration.

Abstract: A device (10) is disclosed for measuring the concentration of metal ions in solution, particularly lead in blood. The device comprises a mercury free electrode (16), which is separated from the test solution (21) by a layer of material (20) which permits passage therethrough of the ions to be measured. In preferred embodiments an insulating layer (18) having an array of photoablated holes (19) is disposed between the electrode and the ion-permeable layer (20). Also disclosed are methods for operating the device and measuring ion concentration using anodic stripping voltametry, and assay kits incorporating devices as described together with appropriate meters and circuitry.

Abstract: The present invention provides an arrangement of equipment and an overall process for the measurement and control of active bleach concentration in a bleach environment of an industrial laundry or cleaning system. As a preferred embodiment the primary piece of equipment which renders the overall system especially useful in controlling, for example, hypochlorite ion in a bleach environment is a membrane-shielded amperometric probe. The probe is designed and membrane selected to be highly selective to fluctuations in hypochlorite ion concentration.

Abstract: A method for detecting and identifying a chemical substance in various phases such as a vapor phase and a liquid phase. The chemical substance being measured is diffused into a predetermined phase. Then, an electric state at an electrode existing in the predetermined phase is detected as a change with time based on the diffusion and absorption of the chemical substance on the electrode. A pattern of the change of the electric state with time is prepared. A fitting function based on the pattern is set and parameters of the chemical substance being measured are found. A distance between the parameters of the chemical substance being measured and parameters of the reference substance which is detected is determined.

Abstract: An analyzer apparatus for analyzing components of a sample has a conduit and an electrochemical sensor in the conduit. The sample is passed through the conduit using a carrier liquid that is immiscible with the sample and non-wetting of the inner wall of the conduit to reduce instabilities in the apparatus due to undue fluid movement.

Abstract: An amperometric dual-electrode sensor having an operating electrode inside a passivable metal electrode used as the counter electrode is provided by the invention. A method for measuring the concentration of a compound or ions in a sample is also provided by this invention. In particular, a method of measuring hydrogen peroxide in a sample is described.

Abstract: A method for detecting organic molecules such as benzene, xylene, ethylbenzene and toluene present in trace quantities in aqueous solutions is provided. The method uses a zeolite having a multiple cage structure, specifically cages of two different volumes. The zeolite is chosen so that the organic molecules are able to access the zeolite on the basis of size. The small cages contain electroactive ions therein and the larger cages contain electroinactive counter cations therein. An aqueous liquid sample to be tested for small molecules is flowed into contact with the zeolite whereby at least some of the electroactive ions in the small cages are released into the aqueous liquid sample by small molecules entering the larger cages and coupling with the electroactive ions in the smaller cages and exiting the zeolite.

Abstract: Provided is a method and apparatus for detecting electroinactive ions, and electroinactive ions solvated by small molecules including water. The method and apparatus utilizes a microporous ion exchange material such as a zeolite containing initially an electroactive species contained within the pores. The method operates on the principle that when charged species present in solution can access the pores of the microporous material, an ion-exchange reaction will occur whereupon the electroactive species will exit the microporous material, being replaced by the charged species. The electroactive species, upon exiting the microporous material, undergoes electrochemical reduction or oxidation at an electrode having a sufficiently high potential applied thereto. The method and detector disclosed herein is size selective since for example zeolites with a pore size comparable to that of the solvated ion to be detected but smaller than other electrolyte components can be utilized.

Abstract: A method of measuring the concentration of ions in a solution, for example the concentration of solvated H.sup.+ ions i.e. the pH, comprises applying an a. c. signal across an ion-sensitive material immersed in the solution and measuring the complex impedance of the ion-sensitive material at a frequency at which the out-of-phase component of the impedance is sensitive to changes in pH. A probe for use in the method comprises two metal electrodes encased in pH sensitive glass, or two electrodes coated independently with ion-sensitive glass, then fritted together.

Abstract: When determining an activity of particular predetermined ions in a sample liquid by use of a device for measuring ionic activity including a pair of ion-selective electrodes which are selectively responsive to particular predetermined ions, a pair of spotting holes through which a sample liquid and a reference liquid are respectively supplied to the ion-selective electrodes and a porous bridge which communicates the spotting holes with each other so as to permit the sample liquid and the reference liquid spotted to the spotting holes to electrically contact with each other, for instance, the sample liquid is first spotted to one of the spotting holes of the device for measuring ionic activity with a first spotting tool, and at least one of the first spotting tool and the device for measuring ionic activity is thereafter moved to remove the first spotting tool away from the device for measuring ionic activity.

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: This invention relates to a novel geo-electro-chemical sampling electrode and process. More specifically, this invention pertains to a novel ion collection electrode, and process, which can be used in the remote sampling of ions contained in ground water. This invention consists of a geo-electrochemical sampling apparatus comprising a hollow electrically non-conductive casing; an opening in the casing for enabling ions to be transported from the exterior of the casing to the interior of the casing, a cathode positioned in the interior of the casing, and electrically connected to the exterior of the casing; and, ion exchange resin contained in the interior of the casing between the cathode and the opening.

Abstract: A solid state ion-selective electrode device to detect a selected ion species in solution an electrode consisting of a homogeneous solid mixture. The mixture is a solid electrolyte composition possessing ionic conductivity and polyvinyl chloride, and optionally graphite. The electrode is substantially free of metallic silver. An electrical connection operates as a contact between the electrode device and a reference source. Methods for detecting the selected ion species in solutions, such as biological samples utilizing the above described electrodes, are also disclosed.

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: A method of monitoring ion mobility in an electro-conductive fluid, such as an electrolyte in a lead-acid battery to determine the state of charge of the battery, includes the steps of immersing a pair of test electrodes in the electro-conductive fluid, and generating a test signal having a pulsed waveform. The pulsed waveform of the test signal has a voltage which remains constant over a predetermined portion of the signal's period, that portion being selected to ensure that ion mobility in the electro-conductive fluid has reached a steady state velocity. The method further includes the steps of applying the test signal to the pair of test electrodes to cause a current to flow through the test electrodes and the electro-conductive fluid, and sensing the current flow through the test electrodes and fluid. The sensed current is indicative of ion mobility in the electro-conductive fluid.