Patent US3826971A successfully refreshed from Google Patents.
US3826971A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Determination of sulfate using ferric ion-selective electrode
Assignee: United States Department of the Interior
•
Filing: 1973-04-12
•
Granted: 1974-07-30
•
Expires: 1993-04-12
Abstract
Abstract Sulfate ion concentration in aqueous solution is determined by initially adding a known concentration of ferric ion to the solution, and adjusting the pH of the solution to a suitable value, whereby ferric ion is complexed by the sulfate ion. The activity of the remaining, uncomplexed ferric ion is then measured by means of a ferric ion-selective electrode comprising a glass of the formula FenGexSbySez, where n is about 1.5 to 3.0, x is about 27 to 29, y is about 11 to 13 and z is about 59 to 61.
Inventors
- 👤 R Jasinski
- 👤 I Trachtenberg
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 23:53
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/26; G01N27/28; G01N27/30; G01N27/36
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
30 words
The method of claim 1 in which the ferric iron is initially added in an amount sufficient to provide a concentration of about 10 3 moles per liter of solution.
Claim 2
Dependent Claim
18 words
The method of claim 1 in which the pH of the solution is initially adjusted to about 2.
Claim 3
Dependent Claim
20 words
The method of claim 1 in which the glass has the formula FenGe28Sb12Se60, where n is about 1.5 to 3.0.
Claim 4
Dependent Claim
10 words
The method of claim 4 in which n is 2.0.
References Cited (Backward Citations)
US3709811A
Cited
US3709813A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-07-29 | 1978-01-28 | 1978-07-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-07-29 | 1982-01-28 | 1982-07-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-07-29 | 1986-01-28 | 1986-07-30 | $7700.00 | Window Closed / Lapsed |