Untersuchungen zur Hydrophilie und Selektivität polymerer stationärer Phasen für die Ionenaustauschchromatographie

The presented research focused on the synthesis of porous polymer particles, which can be applied as column packings in ion chromatography, and their characterization regarding their hydrophilic properties. The methodological approach comprised all aspects of the manufacturing process of IC columns. Based on an established hydrophobic DVB-EVB polymer as reference material, the selection of hydrophilic monomers and their use in the seeded polymerization process developed by UGELSTAD was carried out. The preparation of anion exchangers by functionalization of the polymers produced and the required characterization for the determination of porosity and polarity followed. A hydrophilic polymer library was produced successfully and characterized in view of the in-fluence of the support material’s hydrophilicity on the selectivity in ion chromatography. The required use of new monomers additionally aimed at enlarging the understanding of possi-bilities and limitations of the UGELSTAD process when using hydrophilic components as reac-tants and additives. The investigation of the polymers and the associated anion exchangers served to obtain new insights into the selectivity of bromate and to create a basis for the prediction of selectivity properties by the examination of non-functionalized polymers. In the course of polymer synthesis, the production of various support materials based on non-styrenic monomers was successful. Additionally, different functionalization methods could be applied, whereby anion exchangers with varying functional groups were created. The porosity was characterized using inverse size exclusion chromatography, which could be supplemented by the nitrogen adsorption method. The hydrophilicity was first considered on the basis of the relative retention of two analytes in ion chromatography and reversed phase liquid chromatography. For a deeper understanding, the methods of methylene and eluent selectivity as well as the determination of excess adsorption isotherms of water on surfaces were used. Thereby it could be shown that the tendency of different polymers to adsorb a water layer has a decisive influence on the selectivity of bromate in relation to chloride.