Patent ID: 8343771

Claim:
A method of measuring the concentration of an analyte in an aqueous solution that comprises the steps of: obtaining an aqueous solution containing an analyte, wherein said analyte is iron; providing a cyanine indicator; wherein said cyanine indicator is selected from the group consisting of 1,1′,3,3,3′,3′-hexamethylindodicarbocyanine iodide, 2-[2-[2-chloro-3-[2-[1,3-dihydro-3,3-dimethyl-1-(4-sulfobutyl)-2H-indol-2-ylidene]-ethylidene]-1-cyclohexen-1-yl]-ethenyl]-3,3-dimethyl-1-(4-sulfobutyl)-3H-indolium hydroxide, 1,1′,3,3,3′,3′-4,4′,5,5′-di-benzo-2,2′-indotricarbocyanine perchlorate, 2-[2-[2-chloro-3-[2-(1,3-dihydro-1,3,3-trimethyl-2H-indol-2-ylidene)-ethylidene]-1-cyclohexen-1-yl]-ethnyl]-1,3,3-trimethyl-3H-indolium chloride, and 2-[7-[1,3-dihydro-3,3-dimethyl-1-(4-sulfobutyl)-2H-indol-2-ylidene]-hepta-1,3,5-trienyl]-3,3-dimethyl-1-(4-sulfobutyl)-3H-indolium hydroxide placing said aqueous solution in fluid communication with said cyanine indicator; measuring an absorbance change of said cyanine indicator; and comparing the absorbance change of said cyanine indicator with a calibration curve of the absorbance change of samples containing known concentrations of said analyte to determine the concentration of said analyte; wherein said absorbance change is proportional to the concentration of said analyte in said aqueous solution.