US4303409A
Expired / Lapsed
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Method, composition and test strip for colorimetric analysis of ascorbic acid
Assignee: Shionogi and Co Ltd
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Filing: 1980-04-15
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Granted: 1981-12-01
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Expires: 2000-04-15
Abstract
Abstract A system composed of a complex of a chelating agent with a polyvalent metal ion in its higher valency, an indicator capable of reacting with said metal ion in its lower valency and a buffering agent is disclosed as a composition and a test strip useful for colorimetric analysis of ascorbic acid present in body fluid.
Inventors
- 👤 Yasunao Ogawa
- 👤 Kaoru Ishitobi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 09:17
CPC Classifications
G; G01; G01N; G01N33/00; G01N33/48; G01N33/50; G01N33/82; Y; Y10; Y10T; Y10T436/00; Y10T436/10; Y10T436/108331; Y10T436/14; Y10T436/142222
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
102 words
A composition for colorimetric analysis of ascorbic acid by the formation of colored complexes of a polyvalent metal ion in its lower valency which comprises: a complex of a chelating agent selected from the group consisting of ethylenediaminetetraacetic acid, trans-1,2-cyclohexanediamine-N,N,N',N'-tetraacetic acid, diethylenetriamine-N,N,N',N'',N'''-pentaacetic acid, triethylenetetramine-N,N,N',N''',N''''-hexaacetic acid and alkali metal salts thereof with a polyvalent metal ion in its higher valency; an indicator capable of reacting with said metal ion in its lower valency selected from the group consisting of o-phenanthroline, 4,7-diphenyl-1,10-phenanthroline 2,2'-bipyridine, cuproine, neocuproin and 2,2',2"-terpyridine; and a buffer capable of maintaining the pH value of the composition to from 3 to 6.5.
Claim 2
Dependent Claim
102 words
A composition for colorimetric analysis of ascorbic acid by the formation of colored complexes of a polyvalent metal ion in its lower valency which comprises: a complex of a chelating agent selected from the group consisting of ethylenediaminetetraacetic acid, trans-1,2-cyclohexanediamine-N,N,N',N'-tetraacetic acid, diethylenetriamine-N,N,N',N'',N'''-pentaacetic acid, triethylenetetramine-N,N,N',N''',N''''-hexaacetic acid and alkali metal salts thereof with a polyvalent metal ion in its higher valency; an indicator capable of reacting with said metal ion in its lower valency selected from the group consisting of o-phenanthroline, 4,7-diphenyl-1,10-phenanthroline 2,2'-bipyridine, cuproine, neocuproin and 2,2',2"-terpyridine; and a buffer capable of maintaining the pH value of the composition to from 3 to 6.5.
Claim 3
Dependent Claim
26 words
A composition as claimed in claim 1, wherein the polyvalent metal ion is one selected from the group consisting of iron, copper, cobalt and nickel ions.
Claim 4
Dependent Claim
24 words
A composition as claimed in claim 1, wherein said buffer is capable of maintaining the pH value of the composition from 4 to 6.
Claim 5
Dependent Claim
24 words
A method for colorimetric analysis of ascorbic acid which comprises contacting the composition of claim 1 or 2 with a solution containing ascorbic acid.
Claim 6
Dependent Claim
13 words
A method according to claim 4, wherein said solution is a body fluid.
Claim 7
Dependent Claim
104 words
A test strip for colorimetric analysis of ascorbic acid by the formation of colored complexes of a polyvalent metal ion in its lower valency, which comprises: a bibulous body retaining a complex of a chelating agent selected from the group consisting of ethylenediamine tetraacetic acid, trans-1,2-cyclohexanediamine-N,N,N',N'-tetraacetic acid, diethylenetriamine-N,N,N',N'',N'''-pentaacetic acid, triethylenetetramine-N,N,N',N''',N''''-hexaacetic acid and alkali metal salts thereof with a polyvalent metal ion in its higher valency; an indicator capable of reacting with said metal ion in its lower valency selected from the group consisting of o-phenanthroline, 4,7-diphenyl-1,10-phenanthroline, 2,2'-bipyridine, cuproine, neocuproine and 2,2',2"-terpyridine; a buffering agent; a dye for adjusting background color and a dispersing agent.
Claim 8
Dependent Claim
104 words
A test strip for colorimetric analysis of ascorbic acid by the formation of colored complexes of a polyvalent metal ion in its lower valency, which comprises: a bibulous body retaining a complex of a chelating agent selected from the group consisting of ethylenediamine tetraacetic acid, trans-1,2-cyclohexanediamine-N,N,N',N'-tetraacetic acid, diethylenetriamine-N,N,N',N'',N'''-pentaacetic acid, triethylenetetramine-N,N,N',N''',N''''-hexaacetic acid and alkali metal salts thereof with a polyvalent metal ion in its higher valency; an indicator capable of reacting with said metal ion in its lower valency selected from the group consisting of o-phenanthroline, 4,7-diphenyl-1,10-phenanthroline, 2,2'-bipyridine, cuproine, neocuproine and 2,2',2"-terpyridine; a buffering agent; a dye for adjusting background color and a dispersing agent.
Claim 9
Dependent Claim
41 words
A test strip as claimed in claim 6, wherein the bibulous body is one selected from the group consisting of paper, filter paper, silica gel paper, DEAE cellulose paper, cloth, felt and a sintered porous body of glass or ceramic powder.
Claim 10
Dependent Claim
27 words
A test strip as claimed in claim 6, wherein the polyvalent metal ion is one selected from the group consisting of iron, copper, cobalt and nickel ions.
Claim 11
Dependent Claim
29 words
A test strip as claimed in claim 6, wherein the buffering agent is capable of maintaining pH value of the strip in wet state to from 3 to 6.5.
Claim 12
Dependent Claim
26 words
A test strip as claimed in claim 6, wherein the dispersing agent is one selected from the group consisting of polyvinylpyrrolidone, hydroxypropyl cellulose and polyethylene glycol.
Claim 13
Dependent Claim
28 words
A method for colorimetric analysis of ascorbic acid which comprises contacting the test strip of claim 6, 7, 8, 9 or 11 with a solution containing ascorbic acid.
Claim 14
Dependent Claim
13 words
A method according to claim 11, wherein said solution is a body fluid.
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) | 1984-11-30 | 1985-06-01 | 1985-12-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-11-30 | 1989-06-01 | 1989-12-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-11-30 | 1993-06-01 | 1993-12-01 | $7700.00 | Window Closed / Lapsed |