US4160696A
Expired / Lapsed
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Ascorbic acid determination
Assignee: Eastman Kodak Co
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Filing: 1976-08-23
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Granted: 1979-07-10
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Expires: 1996-08-23
Abstract
Abstract Ascorbic acid in a sample such as blood serum is quantitatively assayed by converting the ascorbic acid to dehydroascorbic acid with ascorbic acid oxidase and reacting the dehydroascorbic with a coupling substance such as phenylenediamine to produce a detectable product. The ascorbic acid oxidase and coupling substance can be combined to form a reagent composition which can be incorporated into integral multilayer elements to form a test element.
Inventors
- 👤 Tai-Wing Wu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 03:09
CPC Classifications
C; C12; C12Q; C12Q1/00; C12Q1/26; C12N; C12N9/00; C12N9/0004; C12N9/0055; C12N9/0057; C12N9/0063; C12Y; C12Y110/00; C12Y110/03; C12Y110/03003
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
75 words
A composition for the detection of ascorbic acid comprising a dry mixture of sufficient ascorbic acid oxidase, coupling substance and buffer as to provide upon addition of water an aqueous composition buffered to a pH of between about 5.7 and about 8.7 and comprising at least about 10 μg/ml of ascorbic acid oxidase, and from about 5×10 -3 to about 10 -2 M coupling substance which interacts with dehydroascorbic acid to produce a detectable product.
Claim 2
Dependent Claim
75 words
A composition for the detection of ascorbic acid comprising a dry mixture of sufficient ascorbic acid oxidase, coupling substance and buffer as to provide upon addition of water an aqueous composition buffered to a pH of between about 5.7 and about 8.7 and comprising at least about 10 μg/ml of ascorbic acid oxidase, and from about 5×10 -3 to about 10 -2 M coupling substance which interacts with dehydroascorbic acid to produce a detectable product.
Claim 3
Dependent Claim
15 words
The composition of claim 1 wherein the ascorbic acid oxidase is from Cucurbita pepo medullosa.
Claim 4
Dependent Claim
18 words
An aqueous composition as described in claim 1 wherein the coupling substance is an o-, m- or ρ-phenylenediamine.
Claim 5
Dependent Claim
58 words
An aqueous composition for the detection of ascorbic acid, said compostion being buffered to a pH of between about 5.7 and about 8.7 and comprising at least about 10 μg/ml of ascorbic acid oxidase and from about 5×10 -3 to about 10 -2 M of a coupling substance which interacts with dedydroascorbic acid to produce a detectable product.
Claim 6
Dependent Claim
58 words
An aqueous composition for the detection of ascorbic acid, said compostion being buffered to a pH of between about 5.7 and about 8.7 and comprising at least about 10 μg/ml of ascorbic acid oxidase and from about 5×10 -3 to about 10 -2 M of a coupling substance which interacts with dedydroascorbic acid to produce a detectable product.
Claim 7
Dependent Claim
18 words
An aqueous composition as described in claim 4 buffered to a pH of between about 6.8 and 7.2.
Claim 8
Dependent Claim
17 words
An aqueous composition as described in claim 4 wherein the ascorbate oxidase is from Cucurbita pepo medullosa.
Claim 9
Dependent Claim
18 words
An aqueous composition as described in claim 4 wherein the coupling substance is a o-, m- or ρ-phenylenediamine.
Claim 10
Dependent Claim
51 words
An aqueous composition for the detection of ascorbic acid comprising at least about 10 μg/ml of ascorbic acid oxidase, an o-, m- or ρ-phenylenediamine in a concentration of from about 5×10 -3 to about 10 -2 M and buffer, said composition having a pH of between about 6.8 and about 7.2.
Claim 11
Dependent Claim
51 words
An aqueous composition for the detection of ascorbic acid comprising at least about 10 μg/ml of ascorbic acid oxidase, an o-, m- or ρ-phenylenediamine in a concentration of from about 5×10 -3 to about 10 -2 M and buffer, said composition having a pH of between about 6.8 and about 7.2.
Claim 12
Dependent Claim
66 words
An element for the detection of ascorbic acid comprising a spreading layer and a reagent layer in fluid contact under conditions of use and containing ascorbic acid oxidase at a concentration of between about 0.10 and about 0.60 g/m 2 and a coupling substance at a concentration of between about 0.01 and about 1.0 g/m 2 which interacts with dehydroascorbic acid to produce a detectable product.
Claim 13
Dependent Claim
66 words
An element for the detection of ascorbic acid comprising a spreading layer and a reagent layer in fluid contact under conditions of use and containing ascorbic acid oxidase at a concentration of between about 0.10 and about 0.60 g/m 2 and a coupling substance at a concentration of between about 0.01 and about 1.0 g/m 2 which interacts with dehydroascorbic acid to produce a detectable product.
Claim 14
Dependent Claim
15 words
The element of claim 9 wherein the ascorbic acid oxidase is from Cucurbita pepo medullosa.
Claim 15
Dependent Claim
15 words
The element of claim 9 wherein the coupling substance is an o-, m- or ρ-phenylenediamine.
Claim 16
Dependent Claim
95 words
An element for the detection of ascorbic acid in a liquid, the element comprising a spreading layer, a reagent layer and an indicator layer all in fluid contact under conditions of use and a support, the reagent layer intervening the spreading layer and the indicator layer and the indicator layer intervening the reagent layer and the support, the reagent layer containing ascorbic acid oxidase at a concentration of between about 0.10 and about 0.60 g/m 2 and the indicator layer containing o-phenylenediamine at a concentration of between about 0.01 and about 1.0 g/m 2 .
Claim 17
Dependent Claim
95 words
An element for the detection of ascorbic acid in a liquid, the element comprising a spreading layer, a reagent layer and an indicator layer all in fluid contact under conditions of use and a support, the reagent layer intervening the spreading layer and the indicator layer and the indicator layer intervening the reagent layer and the support, the reagent layer containing ascorbic acid oxidase at a concentration of between about 0.10 and about 0.60 g/m 2 and the indicator layer containing o-phenylenediamine at a concentration of between about 0.01 and about 1.0 g/m 2 .
Claim 18
Dependent Claim
81 words
An element for the detection of ascorbic acid in a liquid, the element comprising a spreading layer, a reagent layer and an indicator layer all in fluid contact under conditions of use, the reagent layer comprising ascorbic acid oxidase at a concentration of between about 0.10 and about 0.60 g/m 2 and the indicator layer comprising a coupling substance at a concentration of between about 0.01 and about 1.0 g/m 2 which interacts with dehydroascorbic acid to produce a detectable product.
Claim 19
Dependent Claim
81 words
An element for the detection of ascorbic acid in a liquid, the element comprising a spreading layer, a reagent layer and an indicator layer all in fluid contact under conditions of use, the reagent layer comprising ascorbic acid oxidase at a concentration of between about 0.10 and about 0.60 g/m 2 and the indicator layer comprising a coupling substance at a concentration of between about 0.01 and about 1.0 g/m 2 which interacts with dehydroascorbic acid to produce a detectable product.
Claim 20
Dependent Claim
25 words
The element of claim 13 wherein the layer containing said ascorbic acid oxidase is buffered to a pH of between about 5.7 and about 8.7.
Claim 21
Independent Claim
75 words
A method for detecting ascorbic acid comprising the steps of: (a) contacting in an aqueous medium a sample for analysis and a composition buffered to a pH of betwen about 5.7 and about 8.7 and comprising at least about 10 μg/ml of ascorbic acid oxidase and from about 5×10 -3 to about 10 -2 M of a coupling substance which interacts with dehydroascorbic acid to produce a detectable product and (b) detecting the detectable product.
Claim 22
Independent Claim
75 words
A method for detecting ascorbic acid comprising the steps of: (a) contacting in an aqueous medium a sample for analysis and a composition buffered to a pH of betwen about 5.7 and about 8.7 and comprising at least about 10 μg/ml of ascorbic acid oxidase and from about 5×10 -3 to about 10 -2 M of a coupling substance which interacts with dehydroascorbic acid to produce a detectable product and (b) detecting the detectable product.
Claim 23
Dependent Claim
21 words
The method of claim 15 wherein said contacting is performed at a temperature of between about 16° and about 40° C.
Claim 24
Dependent Claim
15 words
The method of claim 15 wherein the ascorbic acid oxidase is from Cucurbita pepo medullosa.
Claim 25
Dependent Claim
15 words
The method of claim 16 wherein the coupling substance is an o-, m- or ρ-phenylenediamine.
Claim 26
Dependent Claim
20 words
The method of claim 17 wherein the aqueous medium is buffered to a pH of between about 6.8 and 7.2.
References Cited (Backward Citations)
US3992158A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-07-09 | 1983-01-08 | 1983-07-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-07-09 | 1987-01-08 | 1987-07-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-07-09 | 1991-01-08 | 1991-07-10 | $7700.00 | Window Closed / Lapsed |