Abstract: An embodiment provides a method for determining the alkalinity of an aqueous sample using an alkalinity sensor, including: monitoring the pH of an aqueous sample using a pH sensor in a sample cell, the pH sensor including a pH sensor electrode made of boron-doped diamond; generating hydronium ions, using a hydronium generator, in the aqueous sample in the sample cell, the hydronium generator including a hydronium-generating electrode; changing the pH of the aqueous sample by causing the hydronium generator to generate an amount of hydronium ions in the aqueous sample; quantifying and converting a current or charge to the number of hydronium ions produced to an end point of the electrochemical titration, the end point correlating to the alkalinity of a sample; and analyzing the alkalinity of the aqueous sample based on the generated amount of hydronium ions and the resulting change in pH monitored by the pH sensor.

Abstract: Embodiments of the invention provide analyte sensors having optimized electrodes and/or configurations of electrode elements as well as methods for making and using such sensors. Typical embodiments of the invention include glucose sensors used in the management of diabetes.

Abstract: A glucose sensor comprises a conducting back electrode. The glucose sensor also comprises a silicon substrate in electrical contact with the conducting back electrode. The glucose sensor also comprises a dielectric layer disposed on the silicon substrate. The glucose sensor also comprises a pH sensing layer disposed on the dielectric layer. The glucose sensor also comprises a chemical layer disposed on the pH sensing layer, wherein the chemical layer is in contact with an aqueous solution. The glucose sensor also comprises a conductive electrode disposed on the dielectric layer, where in the conductive electrode is in contact with the aqueous solution.

Abstract: Provided are site specific chemically modified nanopore devices and methods for manufacturing and using them. Site specific chemically modified nanopore devices can be used for analyte sensing and analysis, for example.

Abstract: The purpose of the present invention is to measure pH of a sample with high accuracy in a pH sensor array, without the use of a glass reference electrode. Each time that a sample is measured, the potential Vrm of the sample is identified, and the identified potential Vrm is used to calculate the pH. The outputs Voi1 and Voi2 of a first element and a second element located near one another in a sensor array are represented as follows. Voi1=Si1×pHi1+Gi1×Vrm+Ci1, Voi2=Si2×pHi2+Gi2×Vrm+Ci2. Voi is the output of the element, Si and Gi are sensitivity coefficients, and Ci is a constant, these values having been derived in advance. Here, where the potential Vrm is constant, and the elements located near one another are presumed to be at equal pH (pHi1=pHi2), the potential Vrm is identified by solving a linear equation with two unknowns.

Abstract: A method of manufacturing a reference electrode for a lithium ion battery comprises charging the battery to a threshold state-of-charge, wherein the battery includes a neutral metal can and a negative electrode, and plating a reference electrode on an interior surface of the neutral metal can by electrically connecting the neutral metal can to the negative electrode, a neutral metal can potential being greater than a negative electrode potential.

Abstract: Methods and devices for purification of different cell components from the same sample are provided.

Abstract: A system for obtaining a pH measurement comprises a disposable probe and a reusable reader. The disposable probe includes an indicating electrode and a reference electrode. The reader operably engages the disposable probe and provides pH information of a sample. The system is configured to be self-calibrating. The system is constructed and arranged to provide pH information based on the potentiometric measurement of the sample solution based on signals received from the at least one indicating electrode and the at least one reference electrode.

Abstract: Systems, devices, and/or methods for use in passive wireless transmission of one or more parameters such as, e.g., pH, temperature, etc. are described. The systems, devices, and/or methods may use a passive sensor located proximate a material and an interrogator that may be used to interrogate the passive sensor and to receive a signal from the passive sensor representative of the one or more parameters.

Abstract: A measuring arrangement, comprising: at least three half-cells, each of which has a pH-sensitive membrane, and a measuring circuit, which is embodied to register a half-cell potential of each half-cell relative to a shared reference potential. The half-cell potential of each half-cell depends on the pH-value of a measured liquid contacting its pH-sensitive membrane. The sensitivity of a first of the three half-cells corresponds to a change of its half-cell potential relative to a change of the pH-value of the measured liquid causing it; the sensitivity of a second of the three half-cells corresponds to a change of its half-cell potential relative to a change of the pH-value of the measured liquid causing it; the sensitivity of a third of the three half-cells corresponds to a change of its half-cell potential relative to a change of the pH-value of the measured liquid causing it.

Abstract: A flowing junction reference electrode comprising a liquid junction member matched with a filter. The junction member and the filter are situated between a reference electrolyte solution and a sample solution. An array of nanochannels spans the junction member and provides fluid communication between the electrolyte solution and the sample solution. The filter is configured to allow a greater flux of electrolyte than that associated with the junction member. Preferably, the number of pores is greater than the number of nanochannels. The filter is preferably configured to have pores with an inner diameter that is the same or less than the inner diameter of the nanochannels. In some embodiment, the resistance of the filter is made lower relative to the resistance of the junction member by selecting suitable length, number, and inner diameter size for the pores of the filter relative to the nanochannels of the junction member.

Abstract: A process for derivatization of an elemental carbon surface comprising exposing the carbon surface to a reaction mixture containing a thiol and a free radical initiator, and inducing decomposition of the initiator to free radicals so that moieties from the thiol become covalently attached to the carbon surface. The process can derivatize carbon with a redox active compound having a functional group which can be converted electrochemically between reduced and oxidized forms. Such derivatized carbon may be used in an electrode of an electrochemical sensor.

Abstract: An ionic probe is provided according to the invention. The ionic probe includes an active electrode configured to generate a measurement signal for an external test fluid, a first reference electrode configured to generate a first reference signal, and an at least second reference electrode configured to generate at least a second reference signal. The measurement signal is compared to the first reference signal and the at least second reference signal in order to determine an ionic measurement of the external test fluid.

Abstract: Methods and apparatus relating to very large scale FET arrays for analyte measurements. ChemFET (e.g., ISFET) arrays may be fabricated using conventional CMOS processing techniques based on improved FET pixel and array designs that increase measurement sensitivity and accuracy, and at the same time facilitate significantly small pixel sizes and dense arrays. Improved array control techniques provide for rapid data acquisition from large and dense arrays. Such arrays may be employed to detect a presence and/or concentration changes of various analyte types in a wide variety of chemical and/or biological processes. In one example, chemFET arrays facilitate DNA sequencing techniques based on monitoring changes in hydrogen ion concentration (pH), changes in other analyte concentration, and/or binding events associated with chemical processes relating to DNA synthesis.

Abstract: Derivatization of an elemental carbon surface is accomplished by exposing the carbon surface to an aprotic solvent containing a hydrazone molecule of formula (I) or the corresponding salt of formula (II) wherein R1 is an organic group, and R2 is an organic group or hydrogen and decomposing the hydrazone in the presence of elemental carbon to create a carbene moiety of formula (III): which attaches to the carbon surface. The attached groups may be redox active so that the derivatized carbon may be used in an electrochemical sensor.

Abstract: Chemical modification of the surface of elemental carbon comprises a first stage of attaching a compound with an azo group to the elemental carbon and then a second stage of decomposing the azo group in the presence of one or more compounds with an olefinic group so that decomposition of the azo group forms radicals attached to the carbon surface and a said radical forms a covalent bond to a said olefinic group. The second stage may proceed as a polymerization of a vinyl monomer with a redox active group such as ferrocene, anthracene or anthraquinone. The resulting polymer-modified carbon may be used in an electrochemical sensor.

Abstract: Carbon nanostructures may be protected and functionalized using a layer-by-layer method whereby functional groups on the carbon nanostructure surface may be further derivatized to incorporate additional functional moieties. Carbon nanostructures functionalized using such a layer-by-layer method may be used to disperse, sort, separate and purify carbon nanostructures and may be used as sensing elements such as voltammetric, amperometric, and potentiometric pH sensors or as biometric sensing elements and electrodes and intracorporeal sensors and electrodes.

Abstract: A system for measuring a solution pH includes a potentiostat with a working electrode made of an electro-conductive solid polymer transducer, an input to receive the potential to be applied between the working electrode and a reference electrode, and an output to transmit a signal representative of the current flowing between a counter electrode and the working electrode, the three electrodes being immerged into the solution. The system further includes a digital processor connected to a digital to analog converter for generating the potential to be applied between the working and the reference electrodes; and to an analog to digital converter for receiving a digital value representative of the current. The digital processor is adapted to modify the potential to maintain the current inside a predetermined range such that the potential is representative of the solution pH when the current is inside the predetermined range.

Abstract: Internally calibrated pH and other analyte sensors based on redox agents provide more accurate results when the redox active reference agent is in a constant chemical environment, yet separated from the solution being analyzed in such a way as to maintain electrical contact with the sample. Room temperature ionic liquids (RTIL) can be used to achieve these results when used as a salt bridge between the reference material and the sample being analyzed. The RTIL provides the constant chemical environment and ionic strength for the redox active material (RAM) and provides an electrolytic layer that limits or eliminates direct chemical interaction with the sample. A broad range of RAMs can be employed in a variety of configurations in such “Analyte Insensitive Electrode” devices.

Abstract: A system for measuring pH includes a substrate and a sensor medium on the substrate. The sensor medium includes at least one oxidized carbon nanostructure and optionally at least one composition immobilized on the at least one oxidized carbon nanostructure. The at least one composition has at least one property that depends on pH. The system further includes at least one measurement system to measure a property of the sensor medium.

Abstract: A pH sensor may include a reference electrode including a p-channel field effect transistor (FET) whose gate includes a diamond surface having a hydrogen ion insensitive terminal, and a working electrode.

Abstract: The present invention provides a PH value detection device and a method of detecting a PH value of a solution. The PH value detection device may comprise: a first electrode and a second electrode, wherein the first electrode and the second electrode are to be inserted into the solution; a power source for applying a bipolar rectangular potential pulse signal to the first electrode and the second electrode; a current detection means connected between the first electrode and the second electrode for detecting a current I flowing through the first electrode and the second electrode; and a calculating unit for calculating the PH value of the solution, based on the detected current I. By means of the above design of the present invention, the use of the fragile glass electrode and the reference electrode, e.g.

Abstract: A chronoamperometric method and device to determine concentration of an electrochemically active species in a fluid and pH of the fluid. A plurality of sets of calibration relationships may be determined for a sensor in an aqueous solution, the sensor having one or more working electrodes and one or more reference electrodes. A first plurality of potentials may be applied across the working and reference electrodes of the sensor in solution, and a first plurality of currents and current differences obtained as a function of the applied first plurality of potentials. Concentration of an electrochemically active species may then be determined as a function of the obtained first plurality of currents and current differences using the plural sets of calibration relationships, and pH of the solution may be determined as a function of the obtained first plurality of currents and current differences using the plural sets of calibration relationships.

Abstract: Detecting a leak from a site in a sealed system with a source of pressurized gas which is capable of passing through the site, a composition of matter which adheres to the surfaces of the system and which is capable of showing the presence of the gas escaping from the site. The method includes: injecting gas into the system to a pressure in excess of the surrounding pressure, and covering the external surface with the composition to identify the location of the site by the interaction of the escaping gas with the composition. The composition is foam that includes a surfactant which forms a least one bubble in the presence of escaping gas and an indicator which changes color in the presence of the escaping gas. The leak is an opening down to at least the size of a hole 0.001? in diameter. A gas detector may also be used.

Abstract: Disclosed are a pH or concentration measuring device and a pH or concentration measuring method which enable measurement in the shortest possible time even in an object to be measured having low buffer capacity.

Abstract: An electrochemical sensor and a method for using an electrochemical sensor are described where the electrochemical sensor comprises a working electrode having thereon one or more redox species that are sensitive to an analyte to be measured and a polymer coating that provides for interaction between the redox species and the analyte.

Abstract: An electrochemical half cell for application in an electrochemical sensor, wherein a fill electrolyte of the half cell is in contact with an external medium via a liquid junction, characterized in that the liquid junction is controllable as regards its permeability and/or its flow.

Abstract: The disclosure provides monolithic electrodes including a substrate defining a walled cavity having a floor, an electrically conductive cathode layer overlaying the cavity floor, an electrically conductive contact pad overlaying the substrate, an electrically conductive via in electrical communication with the cathode layer and the contact pad, and a porous membrane layer overlaying the cavity and defining a chamber formed by the porous membrane layer, the walled cavity, and the cavity floor. The disclosure also provides pH transducers including monolithic indicator and reference electrodes, and methods of making and using monolithic pH electrodes and transducers.

Abstract: A method for operating an ion-sensitive sensor with a measurement circuit which includes an ion-sensitive electrolyte-insulator-semiconductor structure (EIS); wherein the measurement circuit is embodied to issue an output signal which is dependent on ion concentration, especially a pH value, of a measured liquid; and wherein the method comprises the steps of: introducing the ion-sensitive electrolyte-insulator-semiconductor structure into a measured liquid; accelerating charging processes in the region of an insulator layer of the ion-sensitive electrolyte-insulator-semiconductor structure by operating the sensor over a predetermined time span at least a first working point; and dynamically adapting the working point to set a second working point, and registering and processing the output signal of the measurement circuit at the second working point.

Abstract: A reference electrode with an in-situ modified porous diaphragm has at least one housing (1, 201, 301), a first conductor element (4, 204, 304), a modifying electrolyte which is capable of free-flow movement and is contained in the housing (1, 201, 301), and a porous diaphragm (3, 203, 303) which establishes a liquid connection between the modifying electrolyte and a measurement medium (9, 209, 309). The modifying electrolyte seeps out through the porous diaphragm during operation. The modifying electrolyte has a first component and a surface-modifying component which modifies the surface of the porous diaphragm (3, 203, 303) in situ during the passage of the modifying electrolyte. A method for modifying the porous diaphragm in situ is presented.

Abstract: An ionic probe is provided according to the invention. The ionic probe includes an active electrode configured to generate a measurement signal for an external test fluid, a first reference electrode configured to generate a first reference signal, and an at least second reference electrode configured to generate at least a second reference signal. The measurement signal is compared to the first reference signal and the at least second reference signal in order to determine an ionic measurement of the external test fluid.

Abstract: A multiple-electrode ion meter (100) is provided. The multiple-electrode ion meter (100) includes meter electronics (102) configured to receive a plurality of ionic concentration voltage measurements and generate an ionic concentration measurement from the plurality of ionic concentration voltage measurements and three or more individual electrode units (108) in communication with the meter electronics (102). The three or more electrode units (108) generate the plurality of ionic concentration voltage measurements to the meter electronics (102).

Abstract: The invention relates to a pH measuring device containing a reference cell which includes a tank filled with an electrolyte solution and a platinized platinum reference electrode immersed in the tank. The measuring device also contains a measuring cell. The measuring cell contains a platinized platinum measuring electrode which is immersed in the solution to be measured. The measuring device also contains a temperature regulator to ensure that the temperature is the same in the reference cell as in the measuring cell. The measuring device also contains a particle pressure regulator to ensure that the hydrogen partial pressure is the same in the reference cell as in the measuring cell and a fluid pressure regulator to ensure that the pressure is the same in the reference cell as in the measuring cell.

Abstract: A voltammetric pH sensor, especially for characterising wellbore fluids, comprises a plurality of electrodes with a redox active organic compound attached to an electrode and having at least one functional group convertible electrochemically between reduced and oxidized forms with transfer of at least one proton between the compound and surrounding aqueous phase, wherein the compound has at least one substituent group which promotes hydrogen bonding at a said functional group and thereby increases the reaction rate of proton transfer. The substituent group may form an internal hydrogen bond with a redox-convertible group or may enhance polarity to promote electrostatic interaction with water molecules and reduce activation energy.

Abstract: Disclosed is an electrode system capable of more accurately measuring properties of solutions using a porous platinum electrode.

Abstract: The invention relates to methods of preparation of highly sensitive potentiometric sensors with an electroconductive polymer film as a sensing element.

Abstract: Portable device (1) for analysing pH or another variable by electrochemical measurement comprising a sensor (2), a microprocessor (3) and display means (4) for the results of the analysis. The portable device makes it possible to carry out pre-diagnoses quickly and easily without the need for specialist staff.

Abstract: A pH half-cell method and apparatus includes an electrode, a pH sensitive glass membrane and an electrolyte in electrolytic contact with the electrode and membrane. The membrane includes at least about 15 mole percent lithium, and the electrolyte includes a lithium salt as the predominant monovalent cation. The pH half-cell is used with a reference half-cell and meter to provide an electrochemical potential measurement sensor, optionally with both half-cells disposed within a single housing. The lithium salt electrolyte is also used in a method for storing, conditioning, preserving and/or rehabilitating a pH half-cell.

Abstract: A device for adjustment of the pH of a target liquid includes a working electrode (10), an electrolyte chamber (16) which holds an electrolyte (14), a counter electrode (12) in electrical contact with the electrolyte, a junction (18) which spaces the electrolyte from a target liquid (20) when the working electrode is in contact therewith, and a source of current (22), for supplying current to the working electrode for electrolysis of water at the working electrode, whereby the pH of the target solution is adjusted.

Abstract: A system for measuring a solution pH includes a potentiostat with a working electrode made of an electro-conductive solid polymer transducer, an input to receive the potential to be applied between the working electrode and a reference electrode, and an output to transmit a signal representative of the current flowing between a counter electrode and the working electrode, the three electrodes being immerged into the solution. The system further includes a digital processor connected to a digital to analog converter for generating the potential to be applied between the working and the reference electrodes; and to an analog to digital converter for receiving a digital value representative of the current. The digital processor is adapted to modify the potential to maintain the current inside a predetermined range such that the potential is representative of the solution pH when the current is inside the predetermined range.

Abstract: An electrochemical sensor is provided that includes a housing having an outer wall, an axial bore circumscribed by the outer wall, and a barrier wall that aids in defining a reference cavity. The housing further including a plurality of cross members in spaced relation to one another disposed between the axial bore and the outer wall, each cross member defining an aperture. A junction plug is disposed at the distal end of the housing. The junction plug comprises a porous material that enables ionic flow through the junction plug. The sensor enables ionic communication between the target fluid and the reference electrode within the reference cavity through the apertures of the plurality of cross members. In this manner, the sensor provides generally a long, tortuous flow path, or salt bridge, between the target fluid and the reference electrode, resulting in a high resistance factor for the sensor.

Abstract: A method of measuring pH of aqueous liquid with little or no buffer present uses an electrochemical pH sensor which comprises a plurality of electrodes with a redox active organic compound attached to an electrode and having at least one functional group convertible electrochemically between reduced and oxidized forms with transfer of at least one proton between the compound and surrounding aqueous phase, wherein the compound has at least one substituent group which promotes hydrogen bonding at a said functional group and thereby increases the reaction rate of proton transfer. The substituent group may form an internal hydrogen bond with a redox-convertible group or may enhance polarity to promote electrostatic interaction with water molecules and reduce activation energy. Such an electrochemical sensor may be used for pH measurement in computer controlled equipment for processing an aqueous liquid.

Abstract: Provided is a microfluidic device for electrically regulating the pH of a fluid comprising: a first chamber comprising a first electrode; a second chamber comprising a second electrode; a third chamber comprising a third electrode, a metal ion exchange membrane between the first and second chambers; and a hydrogen ion exchange membrane between the first or second chamber and the third chamber.

Abstract: Microelectrodes, microelectrode formation, and methods of utilizing microelectrodes for characterizing properties of localized environments and substrates are provided. A microelectrode can include a tungsten wire comprising a shaft and a conical tip. The conical tip can include an electroactive area. Further, the microelectrode can include an electroactive coating layer covering one or more surface of the tungsten wire. The tungsten wire surfaces can include a surface of the conical tip. An insulating layer can at least partially cover the shaft.

Abstract: A potentiometric sensor includes a housing, in which a reference half cell space and a therefrom separated, measuring half cell space are formed. The reference half cell space contains a reference electrolyte and at least one part of a first potential sensing electrode for sensing a reference potential, and the measuring half cell space is liquid-tightly sealed by a measuring membrane, especially a pH-sensitive glass membrane, and contains an inner electrolyte and at least one part of a second potential sensing electrode for sensing a measuring half cell potential. A passageway extends through a wall of the housing, opens into the reference half cell space, and is sealed relative to a medium surrounding the housing, and wherein the potentiometric sensor has means for producing through the passageway an electrolytic contact between the reference electrolyte and the medium surrounding the housing.

Abstract: Disclosed are a pH or concentration measuring device and a pH or concentration measuring method which enable measurement in the shortest possible time even in an object to be measured having low buffer capacity.

Abstract: An electro-chemical sensor is described having one or more redox species sensitive to a certain analyte and one or more redox species that are insensitive to that analyte, for the purpose of making measurements in a downhole environment in aquifers or oilfield reservoirs.

Abstract: A fluid sampling element is adapted to receive a fluid sample, but also includes a pH sensor element adapted to measure pH of the fluid sample and a reference sensor element. The pH sensor element and the reference sensor element are adapted to generate a potential difference between each other based on the pH of the fluid sample. The pH of the fluid sample can be measured and the fluid sampling element can then be readily disposed of.

Abstract: There is provided a sample preparation device and method for preparing a sample of liquid for detection of impurities. First (40) and second (38) electrodes are provided, located for immersion in a liquid under test. A semipermeable membrane (42) is positioned to protect the first electrode (40) from a body of liquid under test (32). The semipermeable membrane allows the liquid under test to pass therethrough to reach the first electrode, while preventing solids carried in the liquid from reaching the first electrode, the first electrode being positioned to affect the liquid under test in the vicinity of a sensor (36). Particular embodiments feature a hydrophilic membrane to protect the electrodes from suspended solids in the sample, a thin electrode assembly to achieve a faster response and the addition of a heater for temperature control to achieve consistent detection conditions and improved anti-fouling properties.

Abstract: A system for monitoring a pH level of a sample medium is disclosed herein as including a pH probe having a pH-sensitive electrode, a reference electrode and a temperature electrode arranged within a housing of the pH probe. The probe housing generally includes a flexible inner tube and a flexible outer tube, the inner tube being concentrically arranged within the outer tube. Preferably, a size of the probe housing minimizes the amount of trauma introduced by insertion of the pH probe into physiological tissues, muscles or fluids. The system also includes a processing means, which is coupled to the pH probe for determining the pH of the sample medium. A method of forming a pH-sensitive electrode, a method of manufacturing a pH probe, and a method for using a pH probe are also disclosed herein.