Abstract: Described is a method for preserving an aqueous solution comprising a leuco chromogen, comprising adding at least one compound selected from the group consisting of polyoxyethylene alkylamine and polyoxyethylene alkenylamine to the aqueous solution containing a leuco chromogen, and a method for stabilizing a leuco chromogen, comprising allowing the leuco chromogen to coexist in an aqueous solution comprising at least one compound selected from the group consisting of polyoxyethylene alkylamine and polyoxyethylene alkenylamine.

Abstract: It is to provide a method for measuring glycated hemoglobin in a hemoglobin-containing sample, comprising: reacting glycated hemoglobin in the hemoglobin-containing sample with a proteolytic enzyme in the presence of at least one salt selected from the group consisting of a pyridinium salt, a phosphonium salt, an imidazolium salt, and an isoquinolinium salt; reacting the obtained reaction product with fructosyl peptide oxidase; and measuring the generated hydrogen peroxide. The present invention provides a method for accurately measuring glycated hemoglobin in a hemoglobin-containing sample.

Abstract: It is to provide a method for measuring glycated hemoglobin in a hemoglobin-containing sample, comprising reacting the hemoglobin-containing sample with a proteolytic enzyme in the presence of a surfactant, and then reacting the obtained reaction product with fructosyl peptide oxidase, wherein at least one of the former reaction and the latter reaction is performed in the presence of an isothiazolinone derivative; and measuring the generated hydrogen peroxide. The present invention provides a method for accurately and highly sensitively measuring glycated hemoglobin in a hemoglobin-containing sample without being influenced by hemoglobin.

Abstract: It is to provide a method for preserving an aqueous solution comprising a leuco chromogen, comprising adding at least one compound selected from the group consisting of polyoxyethylene alkylamine and polyoxyethylene alkenylamine to the aqueous solution containing a leuco chromogen, and a method for stabilizing a leuco chromogen, comprising allowing the leuco chromogen to coexist in an aqueous solution comprising at least one compound selected from the group consisting of polyoxyethylene alkylamine and polyoxyethylene alkenylamine. The present invention provides a method for preserving an aqueous solution comprising a leuco chromogen for stably preserving the leuco chromogen in an aqueous solution and a method for stabilizing a leuco chromogen.

Abstract: It is to provide a method for measuring glycated hemoglobin in a hemoglobin-containing sample, comprising: reacting glycated hemoglobin in the hemoglobin-containing sample with a proteolytic enzyme in the presence of at least one salt selected from the group consisting of a pyridinium salt, a phosphonium salt, an imidazolium salt, and an isoquinolinium salt; reacting the obtained reaction product with fructosyl peptide oxidase; and measuring the generated hydrogen peroxide. The present invention provides a method for accurately measuring glycated hemoglobin in a hemoglobin-containing sample.