US4707242A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrochemical cell for the detection of noxious gases
Assignee: MSA Safety Inc
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Filing: 1985-07-29
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Granted: 1987-11-17
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Expires: 2005-07-29
Abstract
Abstract The present invention is for an electrochemical cell and method for quantitatively detecting noxious gas which comprises a first working electrode comprising a gas diffusion membrane having bonded thereto a catalytic portion electrochemically reactive with the noxious gas; a second working electrode having electrochemical activity with the oxidation/reduction products produced at the first working electrode; a counter electrode; a reference electrode; an electrolyte; means for containing said electrolyte and said electrodes; means for maintaining a fixed potential on said first working electrode relative to said reference electrode of from about 1.0 to 1.8 volts with respect to the potential of the reversible hydrogen couple of the electrolyte of the cell; and means for maintaining a fixed potential on said second working electrode relative to said reference electrode of from about 1.0 to 2.2 volts with respect to the potential of the reversible hydrogen couple of the electrolyte of the cell, the fixed potential on said working electrode being maintained at a voltage higher than the fixed potential being maintained on said first working electrode.
Inventors
- 👤 Alan A. Schneider
- 👤 David A. Stewart
- 👤 Joseph D. Jolson
- 👤 RaeAnn M. Auel
- 👤 John F. Price
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 19:14
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/26; G01N27/403; G01N27/404; G01N27/4045
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
207 words
An electrochemical cell for quantitatively detecting ethylene oxide comprising: (a) a first working electrode comprising a gas diffusion membrane having bonded thereto a catalytic portion electrochemically reactive with ethylene oxide; (b) a second working electrode having electrochemical activity with oxidation/reduction products produced at the first working electrode; (c) a counter electrode; (d) a reference electrode; (e) an electrolyte in contact with the catalytic portion of the first working electrode and in contact with the second working, counter and reference electrodes; (f) means for containing said electrolyte and said first and second working electrodes, said counter electrode and said reference electrode; (g) means for maintaining a fixed potential on said first working electrode relative to said reference electrode of from above 1.0 to about 1.8 volts with respect to the potential of the reversible hydrogen couple in the electrolyte of the cell; and (h) means for maintaining a fixed potential on said second working electrode relative to said reference electrode of from about 1.0 to 2.2 volts with respect to the potential of the reversible hydrogen couple in the electrolyte of the cell, the fixed potential on said second working electrode being maintained at a voltage higher than the fixed potential being maintained on said first working electrode.
Claim 2
Dependent Claim
207 words
An electrochemical cell for quantitatively detecting ethylene oxide comprising: (a) a first working electrode comprising a gas diffusion membrane having bonded thereto a catalytic portion electrochemically reactive with ethylene oxide; (b) a second working electrode having electrochemical activity with oxidation/reduction products produced at the first working electrode; (c) a counter electrode; (d) a reference electrode; (e) an electrolyte in contact with the catalytic portion of the first working electrode and in contact with the second working, counter and reference electrodes; (f) means for containing said electrolyte and said first and second working electrodes, said counter electrode and said reference electrode; (g) means for maintaining a fixed potential on said first working electrode relative to said reference electrode of from above 1.0 to about 1.8 volts with respect to the potential of the reversible hydrogen couple in the electrolyte of the cell; and (h) means for maintaining a fixed potential on said second working electrode relative to said reference electrode of from about 1.0 to 2.2 volts with respect to the potential of the reversible hydrogen couple in the electrolyte of the cell, the fixed potential on said second working electrode being maintained at a voltage higher than the fixed potential being maintained on said first working electrode.
Claim 3
Dependent Claim
16 words
The electrochemical cell of claim 1 wherein said counter and reference electrodes are a single electrode.
Claim 4
Dependent Claim
33 words
The electrochemical cell of claim 1 wherein the catalytic portion of the first working electrode is selected from the group consisting of palladium, platinum, iridium, ruthenium, rhodium, osmium and mixtures thereof with gold.
Claim 5
Dependent Claim
18 words
The electrochemical cell of claim 3 wherein the catalytic portion of the first working electrode is iridium black.
Claim 6
Dependent Claim
39 words
The electrochemical cell of claim 1 wherein the second working electrode is a gas diffusion membrane having bonded thereto a catalytic portion selected from the group consisting of palladium,, platinum, iridium, ruthenium, rhodium, osmium and mixtures thereof with gold.
Claim 7
Dependent Claim
18 words
The electrochemical cell of claim 5 wherein the catalytic portion of the second working electrode is iridium black.
Claim 8
Dependent Claim
36 words
The electrochemical cell of claim 1 wherein the counter electrode is a gas diffusion membrane having bonded thereto a catalytic portion selected from the group consisting of palladium, platinum, iridium, ruthenium, rhodium, osmium and mixtures thereof.
Claim 9
Dependent Claim
17 words
The electrochemical cell of claim 7 wherein the catalytic portion of the counter electrode is platinum black.
Claim 10
Dependent Claim
33 words
The electrochemical cell of claim 1 wherein the electrolyte is selected from the group consisting of aqueous electrolytes, non-aqueous electrolytes and solid electrolytes that remain stable and inert during operation of the cell.
Claim 11
Dependent Claim
17 words
The electrochemical cell of claim 9 wherein the aqueous electrolyte is an aqueous solution of sulfuric acid.
Claim 12
Dependent Claim
41 words
The electrochemical cell of claim 10 wherein the reference electrode is selected from the group consisting of a normal hydrogen electrode, a saturated calomel electrode, a silver/silver chloride electrode, a glass pH electrode, a mercury/mercury sulfate electrode, and a quinhydrone electrode.
Claim 13
Dependent Claim
27 words
The electrochemical cell of claim 1 wherein the reference electrode is a chloranil/graphite electrode coated with an intimate mixture of polycarbonate or synthetic rubber and sodium sulfate.
Claim 14
Dependent Claim
38 words
The electrochemical cell of claim 1 wherein said means for containing the electrolyte and the electrodes comprise a housing having an electrolyte receiving cavity coextensively positioned therethrough and end plates sealingly mounted at opposite ends of said housing.
Claim 15
Dependent Claim
26 words
The electrochemical cell of claim 1 wherein the first working electrode, the second working electrode and the counter electrode are made from a porous fluorocarbon material.
Claim 16
Dependent Claim
41 words
The electrochemical cell of claim 1 further including (i) means for continuously measuring current flow between the first working electrode and the counter electrode of the cell, said measured current being a measure of the concentration of ethylene oxide being detected.
Claim 17
Dependent Claim
27 words
The electrochemical cell of claim 1 wherein said means for maintaining a fixed potential on said first working electrode relative to said reference electrode is a potentiostat.
Claim 18
Dependent Claim
27 words
The electrochemical cell of claim 1 wherein said means for maintaining a fixed potential on said second working electrode relative to said reference electrode is a potentiostat.
Claim 19
Dependent Claim
14 words
The electrochemical cell of claim 1 wherein the reference electrode is a chloranil/graphite electrode.
Claim 20
Dependent Claim
161 words
An electrochemical cell for quantitatively detecting ethylene oxide comprising: (a) a first working electrode comprising a gas diffusion membrane having bonded thereto a catalytic portion electrochemically reactive with ethylene oxide; (b) a second working electrode having electrochemical activity with oxidation/reduction products produced at the first working electrode; (c) a counter electrode; (d) a reference electrode; (e) an electrolyte in contact with the catalytic portion of the first working electrode and in contact with the second working, counter and reference electrodes; (f) means for containing said electrolyte and said first and second working electrodes, said counter electrode and said reference electrode; (g) means for maintaining a fixed potential on said first working electrode relative to said reference electrode of from about 1.0 to 1.8 volts with respect to the potential of the reversible hydrogen couple in the electrolyte of the cell; and (h) means for maintaining a fixed current through said second working electrode of from about 1 mA to 30 mA.
Claim 21
Dependent Claim
161 words
An electrochemical cell for quantitatively detecting ethylene oxide comprising: (a) a first working electrode comprising a gas diffusion membrane having bonded thereto a catalytic portion electrochemically reactive with ethylene oxide; (b) a second working electrode having electrochemical activity with oxidation/reduction products produced at the first working electrode; (c) a counter electrode; (d) a reference electrode; (e) an electrolyte in contact with the catalytic portion of the first working electrode and in contact with the second working, counter and reference electrodes; (f) means for containing said electrolyte and said first and second working electrodes, said counter electrode and said reference electrode; (g) means for maintaining a fixed potential on said first working electrode relative to said reference electrode of from about 1.0 to 1.8 volts with respect to the potential of the reversible hydrogen couple in the electrolyte of the cell; and (h) means for maintaining a fixed current through said second working electrode of from about 1 mA to 30 mA.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-11-16 | 1991-05-18 | 1991-11-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-11-16 | 1995-05-18 | 1995-11-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-11-16 | 1999-05-18 | 1999-11-17 | $7700.00 | Window Closed / Lapsed |