Patent ID: 6916667

Claim:
A method for determining the presence or amount of an analyte in a sample suspected of containing said analyte, said method comprising; a) providing a combination comprising 1) said sample suspected of containing said analyte, 2) a photosensitizer capable in its excited state of activating oxygen to a singlet state, said photosensitizer being associated with a specific binding pair member that is capable of binding directly or indirectly to the analyte or competing with the analyte for a specific binding pair member, and 3) a composition comprising i) a metal chelate comprising europium, terbium, dysprosium, samarium, osmium, or ruthenium, in at least a hexacoordinated state, and ii) a compound having a structural portion that is a carbon-carbon double bond, wherein one carbon of the carbon-carbon double bond is substituted with an aryl group and oxygen, wherein the other carbon of the carbon-carbon double bond is substituted with an aryl group and an oxygen, sulfur, or nitrogen, wherein one of the aryl groups is electron donating with respect to the other, said compound being associated with a specific binding pair member that is capable of binding directly or indirectly to the analyte or competing with the analyte for the specific binding pair member; b) treating said combination with light or a reactive compound to excite said photosensitizer and cause it to form a singlet state of oxygen; and c) detecting the amount of luminescence emitted from said combination, the presence or amount of said luminescence being related to the presence or amount of said analyte in said sample; wherein the amount of luminescence is related to the amount of analyte in the medium.