Fabrication and characterization of open-tubular CEC modified with tentacle-type metal-chelating polymer chains

A novel stationary phase with tentacle-type metal-chelating polymer chains was fabricated for open-tubular CEC. The preparation procedure of the stationary phase included the synthesis of monomer, silanization of capillary inner wall, in situ polymerization, and metal complexation. The effects of initiator concentration and reaction time on the column capacity were investigated. To compare with the tentacle-type metal-chelating capillary column, a monolayer ligand-modified capillary was also prepared. Immobilized copper(II) capacity of the tentacle-type polymer stationary phase was nearly 900 times higher than that of the monolayer one. The electroosmotic mobility was examined for its dependence on pH as well as phosphate and ACN concentrations. The tentacle-type metal-chelating capillary with high ligand capacity has proven to afford better retention and resolution for the separation of phenylalanine, tryptophan, and tyrosine mixtures and three purine derivatives. The separation was considered to be effected by a combination of ligand exchange and electrophoretic mobility.