Abstract: A sensor for hydrogen in a fluid medium has a chamber for electrolyte with a window which is selectively permeable to hydrogen to allow hydrogen to pass from the fluid medium under test into the electrolyte in the chamber. A plurality of electrodes in contact with the ionic liquid electrolyte are used to observe hydrogen concentration by voltammetry. The electrolyte is an ionic liquid. Applications where such a sensor may be used include a wellbore tool for measuring the content of hydrogen in a subterranean fluid, monitoring of fiber-optic cables for damage by hydrogen, corrosion monitoring, and small-scale process plant where hydrogen is part of a gas stream.

Abstract: An electrode for use in a electrochemical sensor comprises carbon modified with a chemically sensitive redox-active compound, excluding an electrode based on carbon having derivatized thereon two redox-active species wherein at least one of said species is selected from anthraquinone, phenanthrenequinone and N,N?-diphenyl-p-phenylenediamine (DPPD). The invention further provides a pH sensor comprising: a working electrode comprising carbon modified with a chemically sensitive redox active material; and a counter electrode, wherein the ratio of the surface area of the working electrode to the surface area of the counter electrode is from 1:10 to 10:1. Also provided is a pH sensor comprising: a working electrode comprising carbon modified with a chemically sensitive redox active material, and a counter electrode, wherein the area of the working electrode is from 500 ?m2 to 0.1 m2. The uses of these electrodes and sensors are also described.

Abstract: Disclosed herein are devices and methods for the detection, quantification and/or monitoring of analytes. The systems and methods can be used, for example, to rapidly monitor gases downhole in a well.

Abstract: A sensor for monitoring a hydrate inhibitor dissolved in a liquid. The sensor includes an internal reflection window for contacting with the liquid. The sensor further includes a mid-infrared light source for directs a beam of mid-infrared radiation into the window to provide for attenuated internal reflection at an interface between the window and the liquid. The internally reflected mid-infrared beam is passed through a narrow bandpass filter which preferentially transmits mid-infrared radiation over a band of wavelengths corresponding to an absorbance peak of the dissolved hydrate inhibitor to filter internally reflected mid-infrared radiation received from the window. The intensity of the reflected mid-infrared beam transmitted through the filter is measured and used to determine an amount of hydrate inhibitor ion the liquid.

Abstract: Generating hydrogen peroxide in situ in a water environment to mitigate biofouling of a water sensor. A hydrogen peroxide generator submerged in the water environment generates hydrogen peroxide to remove/mitigate biofouling of the water sensor. The water sensor may be an electrochemical sensor and the hydrogen peroxide generator may be an electrochemical system that is integrated with the sensor. The water sensor may be able to operate without interference from the generated hydrogen peroxide.

Abstract: Disclosed herein are devices and methods for the detection, quantification and/or monitoring of analytes. The systems and methods can be used, for example, to rapidly monitor gases downhole in a well.

Abstract: A sensor for hydrogen in a fluid medium has a chamber for electrolyte with a window which is selectively permeable to hydrogen to allow hydrogen to pass from the fluid medium under test into the electrolyte in the chamber. A plurality of electrodes in contact with the ionic liquid electrolyte are used to observe hydrogen concentration by voltammetry. The electrolyte is an ionic liquid. Applications where such a sensor may be used include a wellbore tool for measuring the content of hydrogen in a subterranean fluid, monitoring of fiber-optic cables for damage by hydrogen, corrosion monitoring, and small-scale process plant where hydrogen is part of a gas stream.

Abstract: An electrode for use in a electrochemical sensor comprises carbon modified with a chemically sensitive redox-active compound, excluding an electrode based on carbon having derivatised thereron two redox-active species wherein at least one of said species is selected from anthraquinone, phenanthrenequinone and N,N?-diphenyl-p-phenylenediamine (DPPD). The invention further provides a pH sensor comprising: a working electrode comprising carbon modified with a chemically sensitive redox active material; and a counter electrode, wherein the ratio of the surface area of the working electrode to the surface area of the counter electrode is from 1:10 to 10:1. Also provided is a pH sensor comprising: a working electrode comprising carbon modified with a chemically sensitive redox active material, and a counter electrode, wherein the area of the working electrode is from 500 ?m2 to 0.1 m2. The uses of these electrodes and sensors are also described.

Abstract: An electrode for use in a electrochemical sensor comprises carbon modified with a chemically sensitive redox-active compound, excluding an electrode based on carbon having derivatized thereron two redox-active species wherein at least one of said species is selected from anthraquinone, phenanthrenequinone and N,N?-diphenyl-p-phenylenediamine (DPPD). The invention further provides a pH sensor comprising: a working electrode comprising carbon modified with a chemically sensitive redox active material; and a counter electrode, wherein the ratio of the surface area of the working electrode to the surface area of the counter electrode is from 1:10 to 10:1. Also provided is a pH sensor comprising: a working electrode comprising carbon modified with a chemically sensitive redox active material, and a counter electrode, wherein the area of the working electrode is from 500 ?m2 to 0.1 m2. The uses of these electrodes and sensors are also described.

Abstract: An electrode for use in a electrochemical sensor comprises carbon modified with a chemically sensitive redox-active compound, excluding an electrode based on carbon having derivatised thereron two redox-active species wherein at least one of said species is selected from anthraquinone, phenanthrenequinone and N,N?-diphenyl-p-phenylenediamine (DPPD). The invention further provides a pH sensor comprising: a working electrode comprising carbon modified with a chemically sensitive redox active material; and a counter electrode, wherein the ratio of the surface area of the working electrode to the surface area of the counter electrode is from 1:10 to 10:1. Also provided is a pH sensor comprising: a working electrode comprising carbon modified with a chemically sensitive redox active material, and a counter electrode, wherein the area of the working electrode is from 500 ?m2 to 0.1 m2. The uses of these electrodes and sensors are also described.

Abstract: An electrode for use in a electrochemical sensor comprises carbon modified with a chemically sensitive redox-active compound, excluding an electrode based on carbon having derivatised thereron two redox-active species wherein at least one of said species is selected from anthraquinone, phenanthrenequinone and N,N?-diphenyl-p-phenylenediamine (DPPD). The invention further provides a pH sensor comprising: a working electrode comprising carbon modified with a chemically sensitive redox active material; and a counter electrode, wherein the ratio of the surface area of the working electrode to the surface area of the counter electrode is from 1:10 to 10:1. Also provided is a pH sensor comprising: a working electrode comprising carbon modified with a chemically sensitive redox active material, and a counter electrode, wherein the area of the working electrode is from 500 ?m2 to 0.1 m2. The uses of these electrodes and sensors are also described.

Abstract: An electrode for use in a electrochemical sensor comprises carbon modified with a chemically sensitive redox-active compound, excluding an electrode based on carbon having derivatised thereron two redox-active species wherein at least one of said species is selected from anthraquinone, phenanthrenequinone and N,N?-diphenyl-p-phenylenediamine (DPPD). The invention further provides a pH sensor comprising: a working electrode comprising carbon modified with a chemically sensitive redox active material; and a counter electrode, wherein the ratio of the surface area of the working electrode to the surface area of the counter electrode is from 1:10 to 10:1. Also provided is a pH sensor comprising: a working electrode comprising carbon modified with a chemically sensitive redox active material, and a counter electrode, wherein the area of the working electrode is from 500 ?m2 to 0.1 m2. The uses of these electrodes and sensors are also described.