Electroanalytical method and sensor for hydrogen determination
First Claim
1. In the method of quantitative electroanalytical determination of elemental hydrogen in a fluid medium by means of an amperometric cell comprising at least two electrodes in contact with an aqueous electrolyte to provide a reaction impedance of said cell, said electrolyte being separated from said fluid medium by a membrane that is permeable to said elemental hydrogen but substantially impermeable to said electrolyte to provide a membrane impedance of said cell, said at least two electrodes comprising a first or anodic hydrogen sensing electrode and a second or cathodic counter electrode;
- the improvement consisting essentially of said first or anodic hydrogen sensing electrode having a substantially smooth sensing surface consisting essentially of a platinum metal, and of selecting said membrane impedance to exceed said reaction impedance sufficiently so as to provide for a membrane-controlled operation of said amperometric cell.
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Abstract
A method of and a sensor for quantitative electroanalytical determination of elemental hydrogen in a fluid medium are disclosed. A membrane enclosed amperometric cell is used that has at least two electrodes in contact with an aqueous electrolyte to provide a reaction impedance of the cell; the electrolyte is separated from the fluid medium by a membrane that is permeable to elemental hydrogen but substantially impermeable to the electrolyte and provides a membrane impedance of the cell; the electrodes include an anodic hydrogen sensing electrode and a cathodic counter electrode; the sensing electrode has a polished surface consisting of a platinum metal; further, the membrane is selected such that the membrane impedance exceeds the reaction impedance sufficiently to provide for membrane-controlled operation of the cell.
95 Citations
13 Claims
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1. In the method of quantitative electroanalytical determination of elemental hydrogen in a fluid medium by means of an amperometric cell comprising at least two electrodes in contact with an aqueous electrolyte to provide a reaction impedance of said cell, said electrolyte being separated from said fluid medium by a membrane that is permeable to said elemental hydrogen but substantially impermeable to said electrolyte to provide a membrane impedance of said cell, said at least two electrodes comprising a first or anodic hydrogen sensing electrode and a second or cathodic counter electrode;
- the improvement consisting essentially of said first or anodic hydrogen sensing electrode having a substantially smooth sensing surface consisting essentially of a platinum metal, and of selecting said membrane impedance to exceed said reaction impedance sufficiently so as to provide for a membrane-controlled operation of said amperometric cell.
- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. In a sensor for quantitative electroanalystical determination of elemental hydrogen in a fluid medium, said sensor including an amperometric cell comprising at least two electrodes in contact with an aqueous electrolyte to provide a reaction impedance of said cell, a membrane for separating said electrolyte from said fluid medium, said membrane being permeable to said elemental hydrogen but substantially impermeable to said electrolyte and providing a membrane impedance of said cell, said at least two electrodes comprising an anodic hydrogen sensing electrode and a cathodic counter electrode;
- the improvement consisting essentially of said anodic electrode having a substantially smooth sensing surface consisting of a platinum metal, and said membrane having a thickness in the range of from 10 to 300 μ
m and a hydrogen permeation factor of below 1 (nmol·
μ
m·
m-2 Pa-1 ·
s-1),wherein said substantially smooth sensing surface of the platinum metal has a ratio of apparent surface area;
actual surface area in the range of from 1;
1 to 1;
3.
- the improvement consisting essentially of said anodic electrode having a substantially smooth sensing surface consisting of a platinum metal, and said membrane having a thickness in the range of from 10 to 300 μ
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12. In a sensor for quantitative electroanalytical determination of elemental hydrogen in a fluid medium, said sensor including an amperometric cell comprising at least two electrodes in contact with an aqueous electrolyte to provide a reaction impedance of said cell, a membrane for separating said electrolyte from said fluid medium, said membrane being permeable to said elemental hydrogen but substantially impermeable to said electrolyte and providing a membrane impedance of said cell, said at least two electrodes comprising an anodic hydrogen sensing electrode and a cathodic counter electrode;
- the improvement consisting essentially of said anodic electrode having a substantially smooth sensing surface consisting of a platinum metal, and said membrane having a thickness in the range of from 10 to 300 μ
m and a hydrogen permeation factor of below 1 (nmol·
μ
m·
m-2 ·
Pa-1 ·
s-1) and the aqueous electrolyte is acidic. - View Dependent Claims (13)
- the improvement consisting essentially of said anodic electrode having a substantially smooth sensing surface consisting of a platinum metal, and said membrane having a thickness in the range of from 10 to 300 μ
Specification