Table of Contents:
A set of five new sulfobetain exchangers with inner quaternary amines and outer sulfonic acids could be prepared by applying a grafting reaction. The difference in these five materials is the distance between the charged functional groups varying from one to five methylene groups. Due to the identical reactions and usage of a homologous row of zwitterionic precursors, exchangers with the same core material, identical spacers to the polymeric backbone as well as comparable capacities can be prepared. To verify comparable capacities different methods for the determi- nation of capacities of zwitterionic exchangers are compared.
The behaviour of these materials depending on chain length of the functional groups is examined using separations of inorganic anions with sodium acetate eluents at varying ionic strength and pH. Beside separations of inorganic anions the behavior of the synthesized materials concerning separation of α-amino acids using aqueous eluents is studied.
Further characterisations are carried out using HILIC-mode separations. The volume fraction of acetonitrile – as organic modifier – is increased step by step and the changes in capacity factors of inorganic anions, carboxylic acids, flavonoids as well as pharmacological agents are studied. The accomplished experiments – utilizing the homologous row of zwitterionic exchangers – lead to a further understanding of ZIC and ZIC-HILIC mechanisms and give new opportunities in optimizing stationary phases for ZIC and ZIC-HILIC.