US3836331A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Colorimetric determination of iron
Assignee: Hach Co
•
Filing: 1973-04-19
•
Granted: 1974-09-17
•
Expires: 1993-04-19
Abstract
Abstract 3-(2-PYRIDYL)-5,6-BIS(PHENYLSULFONIC ACID)-1,2,4-TRIAZINE AND CERTAIN SALTS THEREOF, E.G. SODIUM, ARE PROVIDED TOGETHER WITH A METHOD FOR FORMING SUCH COMPOUNDS. These compounds are useful as reagents in the spectrophotometric determination of iron in water or other solutions.
Inventors
- 👤 L Stookey
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 07:04
CPC Classifications
G; G01; G01N; G01N31/00; G01N31/22
Claims Analysis
Total Claims: 1
Claim 1
Independent Claim
15 words
The method of claim 1 wherein the sulfonic acid groups are located at the 4-position.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-09-16 | 1978-03-18 | 1978-09-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-09-16 | 1982-03-18 | 1982-09-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-09-16 | 1986-03-18 | 1986-09-17 | $7700.00 | Window Closed / Lapsed |