USRE30983E
Expired / Lapsed
US
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Colorimetric determination of iron
Assignee: Hach Co
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Filing: 1979-10-17
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Granted: 1982-06-29
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Expires: 1999-10-17
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
- 👤 Lawrence L. Stookey
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 08:21
CPC Classifications
G; G01; G01N; G01N31/00; G01N31/22
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
61 words
In a method for quantitatively determining the presence of iron in a sample solution which includes adding a reagent to a sample solution containing iron in the ferrous state to form a colored complex and colorimetrically determining the iron content, the improvement comprising using 3-(2-pyridyl)-5,6-bis(phenylsulfonic acid)-1,2,4 triazine as the reagent .Iadd.to provide greater sensitivity as compared to that obtained with 3-(2-pyridyl)-5,6-diphenyl-1,2,4-triazine.Iaddend..
Claim 2
Dependent Claim
61 words
In a method for quantitatively determining the presence of iron in a sample solution which includes adding a reagent to a sample solution containing iron in the ferrous state to form a colored complex and colorimetrically determining the iron content, the improvement comprising using 3-(2-pyridyl)-5,6-bis(phenylsulfonic acid)-1,2,4 triazine as the reagent .Iadd.to provide greater sensitivity as compared to that obtained with 3-(2-pyridyl)-5,6-diphenyl-1,2,4-triazine.Iaddend..
Claim 3
Dependent 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) | 1985-06-28 | 1985-12-28 | 1986-06-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-06-28 | 1989-12-28 | 1990-06-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-06-28 | 1993-12-28 | 1994-06-29 | $7700.00 | Window Closed / Lapsed |