Patent ID: 7179658

Claim:
A method of assaying the concentration of an analyte in a sample, comprising: (a) providing sensitized particles comprising an analyte-specific binding partner immobilized thereon; (b) providing a free fluorophore-labeled analyte comprising said labeled analyte attached to a fluorescent moiety; (c) incubating said sample in the presence of a known amount of said sensitized particles and a known amount of fluorophore-labeled analyte under conditions that allow the formation of a first complex comprising said immobilized binding partner bound to said sample analyte and/or a second complex comprising said immobilized binding partner bound to said fluorophore labeled analyte, whereby the fluorescence of said finorophore moiety of said second complex is quenched upon formation of said second complex; (d) subjecting an amount of said incubated sample of step (c) to capillary electrophoresis under conditions that do not require separation of said second complex and said free fluorophore-labeled analyte that is not bound during incubation; and (e) determining said concentration of analyte by detecting a laser-induced fluorescence of said free fluorophore-labeled analyte that is not bound during incubation, wherein said laser-induced fluorescence is directly proportional to the concentration of said analyte in said sample.