Equilibrium studies of lanthanides with silica immobilized chelants

Immobilized chelating agents have been used in construction of fiber optic metal ion sensors. Spectroscopic detection of metallic species in solution is a direct function of the value of the metal/chelant complex formation constant, which in turn is a function of the proton dissociation constants of the chelant. While a great deal of effort has been extended over many years characterizing the formation constants of solution phase metal/chelant interactions, very little work has been focused on the situation where the ligand is immobilized. Design of effective sensors will be dependent on the formation constants of these immobilized ligands. They will discuss the measurement of the Ka's and formation constants for several lanthanide ions and silica immobilized ethylenediamine triacetic acid. The results will be compared to the results obtained in solution