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Preparation of Macroporous Monoliths for Use in Liquid Chromatography : New Approaches
Bok av Anh Mai Nguyen
High performance liquid chromatogarphy (HPLC) is one of the major techniques in separation sciences. Faster separation and higher efficiency are required to meet ever-growing demands. Despite numerous efforts on improving mass transfer in particulate packings discontinuity seems to be the cornerstone. Macroporous continuous beds or monoliths are, therefore, a promising alternative to the particle medium. The work deals with the preparation of new monoliths used as support for HPLC stationary phase. Two different approaches were developed: one based on the polycondensation of epoxy resins which were dispersed in aqueous polyamine phase with the aid of a surfactant. The other involved a traverse of linear polyamides solutions around their upper critical solution temperatures (UCST). The polymers, dissolved in a solvent at temperatures higher than their UCSTs followed by slow cooling to below these temperatures to precipitate the polymers. Partly re-established hydrogen bonds resulted in the formation of crystallites that interconnected into a network structure. The study also deals with surface modifying for chromatographic applications.