[Study of rare earth bifunctional chelate BCPDA-Eu3+ labeling protein].

The authors labeled bovine serum albumin (BSA) with a new europium chelator 4,7-bis(chlorosulfophenyl)-1,10-phenanthroline-2,9-dicarboxylic acid (BCPDA) which was synthesized by solid phase time-resolved fluorescence immunoassay (TRFIA) technology. The process of BCPDA-labeling-BSA reaction was studied. Using Coomassie brilliant blue method, concentrations of BSA and BCPDA were determined in BCPDA-BSA labeled sample. The labeling reaction condition was studied. Labeling ratio and protein labeling recovery were calculated. BCPDA-BSA-Eu3+ complex has a very large Stokes shift (270 nm) and can emit very strong fluorescence band at 611.2 nm which is very narrow (10 nm). BCPDA-BSA-Eu3+ complex exhibits very long fluorescence lifetimes by the experiment demonstration. Also, BCPDA and protein-BCPDA-Eu3+ complex is relatively stable.