Ascorbic acid determination
AssigneeEastman Kodak Company
InventorTai-Wing Wu
Life of this patent
Estimating the term…
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.
Claims19
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 .mu.g/ml of ascorbic acid oxidase, and from about 5.times.10.sup.-3 to about 10.sup.-2 M coupling substance which interacts with dehydroascorbic acid to produce a detectable product.
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 .mu.g/ml of ascorbic acid oxidase and from about 5.times.10.sup.-3 to about 10.sup.-2 M of a coupling substance which interacts with dedydroascorbic acid to produce a detectable product.
An aqueous composition for the detection of ascorbic acid comprising at least about 10 .mu.g/ml of ascorbic acid oxidase, an o-, m- or .rho.-phenylenediamine in a concentration of from about 5.times.10.sup.-3 to about 10.sup.-2 M and buffer, said composition having a pH of between about 6.8 and about 7.2.
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.sup.2 and a coupling substance at a concentration of between about 0.01 and about 1.0 g/m.sup.2 which interacts with dehydroascorbic acid to produce a detectable product.
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.sup.2 and the indicator layer containing o-phenylenediamine at a concentration of between about 0.01 and about 1.0 g/m.sup.2.
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.sup.2 and the indicator layer comprising a coupling substance at a concentration of between about 0.01 and about 1.0 g/m.sup.2 which interacts with dehydroascorbic acid to produce a detectable product.
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 .mu.g/ml of ascorbic acid oxidase and from about 5.times.10.sup.-3 to about 10.sup.-2 M of a coupling substance which interacts with dehydroascorbic acid to produce a detectable product and
- (b) detecting the detectable product.
Dependencies are inferred from the claim text.