Method, composition and test strip for colorimetric analysis of ascorbic acid
AssigneeShionogi & Co., Ltd.
InventorsYasunao Ogawa, Kaoru Ishitobi
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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.
Claims12
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.
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.
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.
Dependencies are inferred from the claim text.