Determination of calcium
AssigneeThe Dow Chemical Company
InventorsWilliam S. Stavropoulos, Bernard J. Thiegs, Robert F. Mack
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Abstract
An improved reagent system for determining calcium by the orthocresolphthalein complexone color reaction. The reagent utilizes an alkaline buffer containing an aminoloweralkanol providing a pH of about 10.2 - 10.5. A method for using the reagent is also described. The composition is stable for extended periods.
Claims8
In a reagent composition useful for determination of calcium in biological fluids by measuring the intensity of color produced by orthocresolphthalein complexone in an aqueous alkaline buffer solution, the composition comprising a solution of orthocresolphthalein complexone, in an aqueous alkaline amine base buffer, the improvement wherein the amine base is an aminoloweralkanol of three or four carbon atoms, having a pK of from about 9.3 to about 10, and wherein the reagent composition has a pH of from about 10.1 to about 10.7.
In a method for determination of calcium comprising the steps of mixing together predetermined quantities of a biological fluid, orthocresolphthalein complexone, as the essential color forming reagent, and an alkaline buffer comprising an amine base, incubating the mixture for a predetermined period under predetermined conditions of temperature, and measuring the intensity of the resulting color, the improvement wherein:
- the amine base is an aminoloweralkanol of three or four carbon atoms, having a pK of from about 9.3 to about 10, and wherein the ingredients are mixed together in proportions sufficient to provide a pH of from about 10.1 to about 10.7 in the ultimate mixture.
Dependencies are inferred from the claim text.