Beckman Instruments, Inc.

Beckman Industrial Corporation

John N Harman, Iii

Radhakrishna M Neti

Youqin Xie

Robert L Chapman

Robert H Jones

John P Frain

R Murty Neti

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.

Solid state ion selective electrode and method of using the same

A solid state sensing element comprising a nonporous, structurally stable, electrically insulating substrate on which is disposed spaced apart pairs of electrodes for contact with moisture. A hygroscopic electrolytic material is located in close proximity to the electrodes as by coating the electrodes with the hygroscopic material. A catalyst is deposited in close proximity to the electrodes and is electrically insulated therefom. The electrodes are connected to a source of potential and current measuring instrumentation. Moisture is trapped by the hygroscopic material and electrolyzed at the electrodes. The catalyst recombines the hydrogen and oxygen thus formed to water so there is no net consumption of water by the element and equilibrium is established at the sensor surface and the atmosphere adjacent the sensor surface. Any change in partial pressure in the atmosphere adjacent the sensor surface is reflected by the movement of water molecules to the area of least concentration which produces a change in amount of moisture being electrolyzed and an increase or decrease in the current required by the element to electrolyze water.

Solid state sensor element

An improved electrochemical cell is described which comprises at least one electrode having increased signal strength achieved by treating at least the working surface of the electrode with a coating of a polytetrafluoroethylene and a catalyst metal selected from the group consisting of platinum and the oxides thereof in an aqueous oligosaccharide solution. Following coating, the electrode is heated to a temperature below the sintering temperature of the polymer to thermally convert the oligosaccharide in the presence of the catalyst metal and drive off the conversion products. An electrode thus treated exhibits a substantially inproved signal strength as compared to an electrode of the same construction which has not been treated in accordance with the invention.

Method for treating electrodes and improved electrochemical cell

A normal pH sensitive glass electrode is deactivated by exposure to thermal treatments at relatively high temperatures of approximately 190.degree. C. for predetermined periods of time until the nominal electrode sensitivity is reduced to very low levels such that the output potentials of such deactivated glass electrode approach the characteristics desired for a theoretically perfect reference electrode. Additionally, a method of forming a deactivated pH glass electrode including the steps of exposing a normal pH or other ion sensitive glass electrode to high temperatures in the order of 190.degree. C. or higher for predetermined periods of time is disclosed. Additionally, there is disclosed an electrode measuring assembly for use in a potentiometric measuring system including, a vessel having a sample solution to be measured therein and a pH measuring electrode pair consisting of a normal pH sensitive glass electrode half cell and a deactivated pH glass electrode half cell disposed in spaced relation and immersed in the sample solution in said vessel, to be measured. The respective normal pH sensitive glass electrode half cell and the deactivated pH glass electrode are calibrated by suitable buffer solutions and a variable span analyzer before the electrode measuring assembly is connected into the potentiometric measuring system.

Reference electrode device

A pH electrode which is capable of withstanding repeated exposures to sterilizing temperatures. An electrode body having a pH sensing member is at least partially filled with a bed of electrochemically inert particles. After an internal reference is inserted into the particle bed, the bed is injected with a quantity of electrolyte which is sufficient to establish continuity between the sensing member and the internal reference, but which is not sufficient to produce destructive internal pressures when the electrode is subjected to sterilizing temperatures. The electrode is completed by forming a seal between the electrode body and the internal reference.

Sterilizable pH electrode and method for producing the same

An improved method for producing an electrode assembly for use in electrochemical gas sensors. A plurality of conductors are attached to one surface of a generally circular electrode blank. These conductors are passed through respective conductor routing holes in an electrically nonconductive mounting member. After the electrode blank is attached to the mounting member, predetermined sections of the electrode blank are cut away to divide the blank into a plurality of electrically isolated regions that are connected to respective conductors. The cut-away sections may then be filled with an electrically nonconductive filling material to provide the electrode assembly with a smooth, flush surface.

Electrochemical gas sensor and method for producing the same

An ion activity or concentration analyzer including an ion selective electrode, a reference electrode and a flow-through electrolytic cell. A sample liquid enclosure conducts a flow of an aqueous sample past the anode and cathode electrodes of an electrolytic cell that is polarized to generate hydrogen and hydroxyl ions. The ion selective and reference electrodes are so positioned, with respect to the cathode electrode, that the hydroxyl ion concentration is increased in the vicinity thereof. This increased hydroxyl ion concentration causes a reduction in the hydrogen ion concentration and thereby substantially eliminates the interfering effect of hydrogen ions on the operation of the ion selective and reference electrodes.

Hydrogen ion interferent reduction system for ion selective electrodes

An improved electrode assembly for use in amperometric gas sensors. A portion of the interior of the electrode assembly that is adjacent to the electrode is filled with an electrochemically inert water-repellant fluid. Once the fluid is in place, a fluid barrier is inserted to cover the fluid and to serve as a foundation for the introduction of a sealing compound. A pressure relief structure, such as a gas bubble, may be provided within the fluid to relieve the pressures incident to the thermal expansion and contraction of the electrode assembly. Because of the water repellancy of the fluid, the electrolyte solution which surrounds the electrode assembly is prevented from migrating into the interior thereof and thereby initiating output current errors.

Amperometric gas sensor, cathode assembly therefor and method of making

An apparatus for compensating for changes in the mass flow rate of a sample gas stream in gas analysis instruments having outputs that are calibrated in terms of the concentration of a component of the sample stream. In instruments in which a pressure regulated sample gas stream is applied to a detector assembly through a flow restrictor such as a sample capillary, a gas flow sensor is connected in series with the flow restrictor to develop a correction signal that varies in accordance with the mass flow rate of the sample stream. A correcting circuit combines the correction signal from the flow sensor with the output signal from the detector assembly to produce a corrected output signal that correctly indicates the concentration of the component of interest.

Gas analysis instrument having flow rate compensation

A solid state ion-sensitive measuring electrode is disclosed in which a filler solution comprising sodium silicate is provided between an outer glass membrane of the electrode and an internal metallic wire which serves as a conductor from the electrode to a meter. The filler solution is inserted into the electrode as a liquid, and is subsequently dehydrated to provide a permanent solid-state matrix which is electrically conducting between the outer glass membrane and the internal wire.

Solid state ion-sensitive electrode and method of making said electrode

In a sulfur dioxide analyzer which measures the content of sulfur dioxide by fluorescence of sulfur dioxide molecules when illuminated by an ultraviolet light source, there is disclosed a converter containing vanadium pentoxide for removal of polynuclear aromatic hydrocarbons which produce interference when sulfur dioxide is measured by fluorescent methodology.

Interference reactor to provide selective SO.sub.2 measurement by

A method and apparatus for removing moisture from a sample stream of gas while preventing dilution of the concentration of components of successive increments of the sample stream of gas.

Thermoelectric gas dryer

A method of analyzing nitric oxide (NO) in a gas stream containing nitrogen dioxide (NO.sub.2) and a scrubber apparatus for selectively removing nitrogen dioxide from a gas stream containing nitric oxide. The scrubber apparatus comprises a container having an inlet port for the gas stream and an outlet port. The scrubber material in the container includes silver carbonate whereby the scrubber has an efficiency of at least about 99% and a capacity of about 11.5 parts per million hours of 99% nitrogen dioxide removal per gram of silver carbonate. The method involves passing the gas stream through a scrubber material containing silver carbonate so as to remove nitrogen dioxide from the gas stream while passing the nitric oxide unattenuated and thereafter conveying the gas stream from the scrubber material to an analyzer for nitric oxide. The gas stream is analyzed with the analyzer to determine the nitric oxide concentration therein.

Growing community of inventors

Placentia, CA, United States of America

John N Harman, Iii