Emission properties of lanthanide chelates

Some lanthanide ions when complexed with UV-absorbing ligands, can efficiently accept energy from the excited state of the ligand and produce highly enhanced emission characteristics of the metal ion. Rare earth complexes have some advantages over organic fluorescent probes such as fluorescein, rhodamines, umbelliferones such as 

The emission-decay profiles of Tb3+, Dy3+, Eu3+ and Sm3+ complexes of pivaloyl trifluoroacetone are shown in Fig. 12.31. A sketch of time resolved fluorometry of Eu3+ with spectral filters and temporal resolution (time windows) is shown in Fig. 12.32. 

MODERN ASPECTS OF RARE EARTHS AND THEIR COMPLEXES 

The coupling of the stable chelate to the biological moiety should be a mild, facile, efficient and reproducible reaction. In antibodies, the free amino groups of lysins are reactive and their modification has no ill effects on the affinity and specificity. Isothiocyanato groups can be used for modification purposes without affecting the high affinity, solubility and specificity of the most tested monoclonal antibodies. 

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