ICP Spectrometric–Vis Separation of Cerium (IV)–Desferal Complex Using 4-Vinylbenzyl Dimethylammonio Pentanesulfonate Zwitterionic Stationary Phase

A new covalently bonded sulfobetaine stationary phase with an outer positive charge and an inner negative charge was synthesized by attachment of zwitterionic molecule to PS/DVB particles by graft polymerization. Desferal (DFOM) is a chelating agent which forms complexes with multiple charged metal ions of biological importance. We could demonstrate that the zwitterionic stationary phase is able to separate the Ce(IV)-DFOM complex by IC-ICP-AES. It could be demonstrated that metal-DFOM separations on zwitterionic stationary phase are mainly driven by a cation exchange mechanism. This is a behavior never before observed using zwitterionic stationary phase. In spite of numerous publications in the literature which confirm that zwitterionic type materials are usually well suited for anion separation, no investigation had been carried out to separate cationic organic compounds. The sulfobetaine column already mentioned exhibited the difference as compared to the commercially ZIC-HILIC and ZIC-pHILIC columns.