Patent ID: 7691647

Claim:
A composition suitable for use as a signal generation component in an immunoassay comprising: a carrier coated with an aminodextran, wherein the density of the aminodextran averages at least about 45 μg per milligram of carrier, and having incorporated therein, at a concentration of at least 0.065 μMole per gram of the carrier, a complex having the formula: M(L1) x (L2) y , wherein M is a metal selected from the group consisting of europium, terbium, dysprosium, samarium, osmium and ruthenium; L1 is a ligand selected from the group consisting of DPP, TOPO, TPPO; L2 comprises a ligand having the formula wherein R is one or more substituents, each substituent comprising an electron donating group; n=3 or 7; x=1-2; and y=2-4.