Patent ID: 7556932

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