US3950231A
Expired / Lapsed
US
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Method of determining hydrogen cyanide
Assignee: Thermo Orion Inc
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Filing: 1974-08-30
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Granted: 1976-04-13
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Expires: 1994-08-30
Abstract
Abstract An improved gas-sensing electrochemical cell for measuring hydrogen cyanide gas in a sample solution. The cell comprises a potentiometric silver ion-sensitive electrode and a reference electrode, both in contact with an internal standard solution comprising an aqueous solution of an argento cyanide complex. A hydrophobic hydrogen cyanide gas-permeable membrane separates the sample solution from the internal solution.
Inventors
- 👤 Martin S. Frant
- 👤 John H. Riseman
- 👤 John A. Krueger
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 15:35
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/26; G01N27/403; G01N27/4035
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
56 words
Method of determining the hydrogen cyanide content of a sample solution comprising the steps of; diffusing said hydrogen cyanide into an electrolyte through a membrane which is permeable to said hydrogen cyanide but substantially impermeable to liquids and ionic constituents thereof, and measuring the cyanide ion activity in said electrolyte with a potentiometric ion selective electrode.
Claim 2
Dependent Claim
56 words
Method of determining the hydrogen cyanide content of a sample solution comprising the steps of; diffusing said hydrogen cyanide into an electrolyte through a membrane which is permeable to said hydrogen cyanide but substantially impermeable to liquids and ionic constituents thereof, and measuring the cyanide ion activity in said electrolyte with a potentiometric ion selective electrode.
Claim 3
Dependent Claim
58 words
Method as defined in claim 1 wherein said diffusing step includes the steps of: placing said membrane between said sample solution and said electrolyte, and allowing the free hydrogen cyanide in said sample solution to diffuse across said membrane so that the partial pressures of said hydrogen cyanide on both sides of said membrane are substantially in equilibrium.
Claim 4
Dependent Claim
25 words
Method as defined in claim 1 including the step of adjusting the pH of said electrolyte in the range between pH 7 and pH 11.
Claim 5
Dependent Claim
21 words
Method as defined in claim 1, including the step of adjusting the pH of said electrolyte to substantially ground pH 8.5.
Claim 6
Dependent Claim
28 words
Method as defined in claim 1 wherein said diffusing step includes the step of acidifying said sample solution to convert all cyanide ions contained therein to hydrogen cyanide.
Claim 7
Dependent Claim
28 words
Method as defined in claim 5, including the step of adjusting the osmolality and temperature of said sample solution to match the osmolality and temperature of said electrolyte.
Claim 8
Dependent Claim
17 words
Method as defined in claim 1, including the step of adding a pH buffer to said electrolyte.
Claim 9
Dependent Claim
13 words
Method as defined in claim 7, wherein the buffer added is boric acid.
Claim 10
Dependent Claim
22 words
Method as defined in claim 1, including the step of adding water soluble cyanide complex of silver or cadmium to said electrolyte.
Claim 11
Dependent Claim
74 words
Method as defined in claim 1, wherein said step of measuring the cyanide ion activity in said electrolyte includes the steps of contacting said electrolyte with a potentiometric ion-selective electrode which is responsive to the activity of silver ions or cadmium ions in said electrolyte contacting said electrolyte with a reference electrode for providing a potential which is substantially independent of the presence of cyanide ions and measuring the potential difference between said electrodes.
Claim 12
Dependent Claim
74 words
Method of determining the hydrogen cyanide content of a sample solution comprising the steps of; diffusing said hydrogen cyanide into an electrolyte, having ions of a soluble cyanide complex of a metal, through a membrane which is permeable to said hydrogen cyanide but substantially impermeable to liquids and ionic constituents thereof, and measuring the cyanide ion activity in said electrolyte with a potentiometric ion selective electrode responsive to the cyanide complex of the metal.
Claim 13
Dependent Claim
74 words
Method of determining the hydrogen cyanide content of a sample solution comprising the steps of; diffusing said hydrogen cyanide into an electrolyte, having ions of a soluble cyanide complex of a metal, through a membrane which is permeable to said hydrogen cyanide but substantially impermeable to liquids and ionic constituents thereof, and measuring the cyanide ion activity in said electrolyte with a potentiometric ion selective electrode responsive to the cyanide complex of the metal.
References Cited (Backward Citations)
US2864747A
Cited
US2912367A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-04-13 | 1979-10-13 | 1980-04-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-04-13 | 1983-10-13 | 1984-04-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-04-13 | 1987-10-13 | 1988-04-13 | $7700.00 | Window Closed / Lapsed |