Patent ID: 7651858

Claim:
Ion-detecting polymeric microspheres for detecting metal ions in a sample, said microspheres comprising a lipophilic ionophore selective for said metal ions, a chromoionophore selective for hydrogen ions, a copolymer having a glass transitional temperature (T g ) of about or below 0° C., and a flourescent dye, wherein said chromoionophore is a chromoionophore that becomes deprotonated when said metal ions are present in said sample, and wherein said deprotonated form of said chromoionophore is absorbent at the frequency of the fluorescence emission of said dye, wherein said copolymer comprises polymerized units of methacrylate monomers, wherein said methacrylate monomers comprise a monomer having an R 1 pendant alkyl group and a monomer having an R 2 pendant alkyl group, wherein R 1 is any of C 1-3 alkyl groups and R 2 is any of C 4-12 alkyl groups.