US4596770A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Assay of peroxidase enzyme activity
Assignee: Baxter Healthcare Corp
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Filing: 1984-06-01
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Granted: 1986-06-24
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Expires: 2004-06-01
Abstract
Abstract The use of aqueous N-methyl pyrrolidone as a solvent for a substrate containing tetraalkyl benzidine chromogen and a peroxide in determining peroxidase enzyme activity provides increased stability of the substrate solution and decreased substrate drift in carrying out enzyme immunoassays or enzyme-linked immunosorbent assays.
Inventors
- 👤 Marc Parham
- 👤 William J. Warren
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 09:05
CPC Classifications
C; C12; C12Q; C12Q1/00; C12Q1/26; C12Q1/28; C12Q2326/00; C12Q2326/10; C12Q2326/12; Y; Y10; Y10S; Y10S435/00; Y10S435/81; Y10S435/963; Y10S435/975
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
84 words
In an enzyme immunoassay or enzyme-linked immunosorbent assay in which 3,3',5,5'-tetraalkyl benzidine chromogen or an acid salt thereof and a peroxide are reacted with a peroxidase in an aqueous buffer, said reaction is stopped by the addition of a stopping agent, and the intensity of the color developed is measured, the improvement which comprises providing said chromogen in solution in an aqueous substrate medium containing 5 to 20% by volume of N-methyl pyrrolidone and an acetate buffer providing a pH from 4 to 7.
Claim 2
Dependent Claim
84 words
In an enzyme immunoassay or enzyme-linked immunosorbent assay in which 3,3',5,5'-tetraalkyl benzidine chromogen or an acid salt thereof and a peroxide are reacted with a peroxidase in an aqueous buffer, said reaction is stopped by the addition of a stopping agent, and the intensity of the color developed is measured, the improvement which comprises providing said chromogen in solution in an aqueous substrate medium containing 5 to 20% by volume of N-methyl pyrrolidone and an acetate buffer providing a pH from 4 to 7.
Claim 3
Dependent Claim
32 words
An assay as claimed in claim 1 in which the concentration of said chromogen is from 1 to 2 mM and the concentration of N-methyl pyrrolidone is 6 to 8% by volume.
Claim 4
Dependent Claim
19 words
An assay as claimed in claim 1 in which said chromogen is 3,3',5,5'-tetramethyl benzidine or an acid salt thereof.
Claim 5
Dependent Claim
31 words
An assay as claimed in claim 2 in which said chromogen is 3,3',5,5'-tetramethyl benzidine or an acid salt thereof and the concentration of N-methyl pyrrolidone is 6 to 8% by volume.
Claim 6
Dependent Claim
27 words
An assay as claimed in claim 1 in which said reaction is stopped by the addition of an aqueous solution of water soluble fluoride at pH 3-6.
Claim 7
Dependent Claim
27 words
An assay as claimed in claim 2 in which said reaction is stopped by the addition of an aqueous solution of water soluble fluoride at pH 3-6.
Claim 8
Dependent Claim
27 words
An assay as claimed in claim 3 in which said reaction is stopped by the addition of an aqueous solution of water soluble fluoride at pH 3-6.
Claim 9
Dependent Claim
26 words
An assay as claimed in claim 4 in which said reaction is stopped by the addition of an aqueous solution of water soluble fluoride at pH3-6.
Claim 10
Dependent Claim
59 words
A stock solution for use in an enzyme immunoassay or enzyme-linked immunosorbent assay procedure comprising reacting 3,3',5,5'-tetraalkylbenzidine chromogen and peroxide with peroxidase in an aqueous substrate medium, said solution comprising an aqueous solution containing 5-50% N-methyl pyrrolidone by volume, 1-10 mM 3,3',5,5'-tetraalkyl benzidine or an acid salt thereof, and an acetate buffer providing a pH from 4 to 7.
Claim 11
Dependent Claim
59 words
A stock solution for use in an enzyme immunoassay or enzyme-linked immunosorbent assay procedure comprising reacting 3,3',5,5'-tetraalkylbenzidine chromogen and peroxide with peroxidase in an aqueous substrate medium, said solution comprising an aqueous solution containing 5-50% N-methyl pyrrolidone by volume, 1-10 mM 3,3',5,5'-tetraalkyl benzidine or an acid salt thereof, and an acetate buffer providing a pH from 4 to 7.
Claim 12
Dependent Claim
46 words
A stock solution for use in an enzyme immunoassay or enzyme-linked immunosorbent assay procedure comprising reacting 3,3',5,5'-tetraalkylbenzidine chromogen and peroxide with peroxidase, said solution consisting essentially of an aqueous solution containing 5-50% N-methyl pyrrolidone by volume and 1-10 mM 3,3',5,5═-tetraalkyl benzidine or an acid salt thereof.
Claim 13
Dependent Claim
46 words
A stock solution for use in an enzyme immunoassay or enzyme-linked immunosorbent assay procedure comprising reacting 3,3',5,5'-tetraalkylbenzidine chromogen and peroxide with peroxidase, said solution consisting essentially of an aqueous solution containing 5-50% N-methyl pyrrolidone by volume and 1-10 mM 3,3',5,5═-tetraalkyl benzidine or an acid salt thereof.
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) | 1989-06-23 | 1989-12-23 | 1990-06-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-06-23 | 1993-12-23 | 1994-06-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-06-23 | 1997-12-23 | 1998-06-24 | $7700.00 | Window Closed / Lapsed |