Synthesis of europium(III) chelates suitable for labeling of bioactive molecules.

Two different kinds of europium(III) chelates, luminescent and nonluminescent, were prepared. The chelates were coupled to bioanalytical reagents, such as antibodies, after activations of the amino group on the chelates with thiophosgene,2,4,6-trichloro-1,3,5-triazine, or iodoacetic anhydride. The reactivities of the activated luminescent chelates in the labeling of antibodies as well as the effects of both the coupling ratio and the linkage group to the luminescence quantum yield of the antibody-bound chelate were studied in aqueous buffer solution.