Patent ID: 7247489

Claim:
A method of detecting target ions in a sample, comprising: (a) providing ion-detecting polymeric microspheres, said microspheres comprising an ionophore selective for said target ions, and a fluorescent chromoionophore, wherein said polymeric microspheres comprise a copolymer having a glass transitional temperature (T g ) of about or below 0° C., 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; (b) contacting said microspheres with a flowing stream of said sample under conditions that allow the ion-selective ionophores to bind and form complexes with the ions, if present in the sample, and to cause deprotonation of the chromoionophore, wherein the ionophore/ion complex causes deprotonation of the chromoionophore, and the target ions are extracted into the bulk of the microsphere where they are complexed by the ion-selective ionophores; (c) exposing the deprotonated chromoionophore, if formed, to an excitation wavelength light source suitable for exciting the deprotonated chromoionophore of the complexes to emit a fluorescence signal pattern; and (d) detecting the fluorescence signal pattern emitted by the complexes, if present, by a detection means for detecting the fluorescence signal pattern, wherein said fluorescence signal pattern is inversely proportional to the amount of said target ions in said sample.