(1) Macrocycle-Based Ion Chromatography. These projects, funded by Dionex Corporation, combine the unusual selectivities of macrocyclic ligands with the separation efficiencies of ion chromatography. Anion exchange and cation exchange columns can be formed by the adsorption or bonding of macrocyclic ligands to reversed phase columns. Capacity gradient separations of anions are achieved by changing the eluent cation from one with high macrocycle affinity to one with low macrocycle affinity during the course of the separation. Capacity gradients exhibit excellent separation characteristics coupled with better baseline stability than conventional gradient systems. Gradient separations of both anions and cations are also possible by changing column temperature during the course of the separation. The variety of macrocyclic ligands, substrates, and separation conditions offers a wide potential for novel research.

     (2) Macrocycle-Based Membrane Separations. These projects, involve the synthesis, characterization, and application of new macrocyclic ligands to the separation of metal cations. New ligands are synthesized in the laboratory of Professor Roger Harrison and subsequently characterized in our laboratory through various methods. The ligands are evaluated for their applicability to cation separations by solvent extraction or by liquid membranes, both bulk liquid membranes and polymer inclusion membranes.