US4207203A
Expired / Lapsed
US
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Uric acid standard solutions
Assignee: Covidien AG
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Filing: 1979-05-04
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Granted: 1980-06-10
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Expires: 1999-05-04
Abstract
Abstract Stable aqueous solutions useful as standards in the determination of uric acid are disclosed. The solutions have a pH of about 6-7 and contain a buffer and a known concentration of uric acid present in solution as a salt of the pH-controlling buffer component. They do not contain any strong base such as lithium carbonate. The standards can be used in connection with either enzymatic or non-enzymatic procedures.
Inventors
- 👤 E. Melvin Gindler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 21:15
CPC Classifications
G; G01; G01N; G01N33/00; G01N33/48; G01N33/50; G01N33/96; Y; Y10; Y10T; Y10T436/00; Y10T436/10; Y10T436/103332; Y10T436/108331
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
72 words
A stable solution useful as a standard in the determination of uric acid, said solution consisting essentially of water, a buffer sufficient to maintain the pH value of the solution at about 6-7, and a known concentration of uric acid present as a soluble salt of the pH-controlling buffer component, said component having a pK value of about 5-7.5, and said solution having excluded therefrom bases with a pK above about 8.
Claim 2
Dependent Claim
72 words
A stable solution useful as a standard in the determination of uric acid, said solution consisting essentially of water, a buffer sufficient to maintain the pH value of the solution at about 6-7, and a known concentration of uric acid present as a soluble salt of the pH-controlling buffer component, said component having a pK value of about 5-7.5, and said solution having excluded therefrom bases with a pK above about 8.
Claim 3
Dependent Claim
18 words
The solution of claim 1 which also contains one or more microbial growth inhibitors and metal chelating agents.
Claim 4
Dependent Claim
16 words
The solution of claim 2 wherein the pH-controlling buffer component has a pK value of 6-7.5.
Claim 5
Dependent Claim
13 words
The solution of claim 3 wherein the buffer comprises a weakly basic amine.
Claim 6
Dependent Claim
13 words
The solution of claim 4 wherein the amine is imidazole, pyridine or collidine.
Claim 7
Dependent Claim
11 words
The solution of claim 5 wherein the pH value is 6.5-7.
Claim 8
Dependent Claim
10 words
The solution of claim 6 wherein the amine is imidazole.
Claim 9
Dependent Claim
15 words
The solution of claim 7 wherein the acidic component of the buffer is benzoic acid.
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) | 1983-06-10 | 1983-12-10 | 1984-06-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-06-10 | 1987-12-10 | 1988-06-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-06-10 | 1991-12-10 | 1992-06-10 | $7700.00 | Window Closed / Lapsed |