Patent ID: 6030842
Filing Date: 2000-02-29
Classification: G01N,Y10T

Abstract:
A method for the determination of free halogen in aqueous solutions comprising:contacting a test solution sample with a reagent composition consisting essentially of a chromogenic indicator material having the formula: ##STR3## where R and R' are selected from the group consisting of hydroxy and amino groups and X,X',Y and Y' are selected from the group consisting of hydrogen, hydroxy, methyl, methoxy, ethyl and ethoxy groups and combinations thereof and;an effective amount of a catalyst to enhance in a non-additive manner the response of the chromogenic indicator material to the presence of free halogen in the test solution sample, said catalyst having the formula: ##STR4## where X,X',Y,Y',R and R' are selected from the group consisting of hydrogen and alkyl groups of up to six carbon atoms, and a buffer to maintain the test composition and test solution sample in a pH range of about from 3.5 to 8.0; and,comparing the color response obtained to color responses from standardized solutions of free halogen and;translating such comparison to the amount of free halogen in the test solution.