Method for measuring component by treating aqueous sample with alpha-keto acid and then converting component to hydrogen peroxide
The present invention provides a method for measuring a component to be measured in a sample, comprising converting the component to be measured in the sample into hydrogen peroxide and measuring the formed hydrogen peroxide in the presence of an α-keto acid using an oxidative-coloring chromogen. The present invention also provides a method for suppressing the influence of a peroxide on a method of converting a component to be measured in a sample into hydrogen peroxide and measuring the formed hydrogen peroxide using an oxidative-coloring chromogen, the suppression method comprising using an α-keto acid. The measuring method and the suppression method of the present invention using an α-keto acid suppress the influence of a peroxide to give an accurate measurement of the component to be measured in the sample.
1. A method for suppressing the influence of a peroxide on a method for measuring hemoglobin A1c in a sample containing peroxides comprising the steps of:
adding an α-keto acid to an aqueous solution containing the sample to react with the peroxides contained therein;
converting hemoglobin A1c into hydrogen peroxide in the aqueous solution; and
reacting the formed hydrogen peroxide with an oxidative-coloring chromogen in the presence of the α-keto acid, whereby
influence of the peroxides other than said formed hydrogen peroxide on said reaction of said hydrogen peroxide with said oxidative-coloring chromogen is suppressed.
2. The method according to claim 1 , wherein the α-keto acid is an α-keto acid selected from the group consisting of pyruvic acid, α-ketoglutaric acid, and oxaloacetic acid.
3. The method according to claim 1 , wherein the oxidative-coloring chromogen is a leuco chromogen.
4. The method according to claim 3 , wherein the leuco chromogen is a phenothiazine derivative.
5. The method according to claim 4 , wherein the phenothiazine derivative is 10-(carboxymethylaminocarbonyl)-3,7-bis(dimethylamino)phenothiazine.
6. The method according to claim 1 , wherein the oxidative-coloring chromogen is an oxidative coupling-type chromogen.
7. The method according to claim 6 , wherein the oxidation coupling-type chromogen is a combination of a coupler and an aniline derivative or a phenol derivative.