Patent ID: 8498682

Claim:
A device for the determination of two analyte concentrations, comprising: an optical sensor comprising an indicator system, said indicator system comprising: a fluorophore that exists in at least a first and a second different form, wherein the form of the fluorophore depends on a concentration of a first analyte, and wherein the different forms are distinguishable based on their respective emissions; a binding moiety that is operably coupled to said fluorophore and capable of binding a second analyte, wherein a ratio of the respective emissions of the fluorophore is independent of the concentration of said second analyte; wherein binding of said second analyte to said binding moiety induces a change in the emission intensity of said fluorophore; at least one light source configured to excite said fluorophore; at least one detector configured to simultaneously detect both said respective emission wavelengths and the emission intensity of said fluorophore; and a controller configured to monitor signals from said at least one detector, wherein said controller comprises an algorithm for determining the concentration of said first analyte based on the ratio of the respective emissions and the concentration of said second analyte based on the emission intensity of said fluorophore, and wherein said algorithm further corrects the concentration of said second analyte for the concentration of said first analyte.