The preparation of macroporous, monodisperse polymeric beads with controlled chemistry and porosity for applications in high performance liquid chromatography.

摘要

Several types of functionalized macroporous polymer beads that can be used as a platform for the production of separation media, polymeric reagents, and supports have been prepared and characterized. Control over the size, chemistry, and porous properties of the beads is accomplished using the staged templated polymerization technique.; The first part of the research is focused on the preparation of reactive styrene beads from functionalized monomers, such as acetoxystyrene and aminostyrene, with divinylbenzene as a crosslinker. An extensive study of the effects of various polymerization parameters on the properties of these reactive beads was carried out in order to achieve fine control over the degree of functionalization and pore structure. The beads are useful for many applications, including size-exclusion high-performance liquid chromatography (HPLC) of small molecules with a molecular weight of less than 1000.; The second part of the research is focused on the preparation of functionalized methacrylate beads with a variety of surface chemistries including carboxylic acid, hydroxyl, and amino groups. These polymers can be prepared by utilizing a protected methacrylate monomer, or in the case of the hydroxyl functionalized beads, 2-hydroxyethyl methacrylate, in the polymerization mixture. One application for the reactive beads is the preparation of highly selective chiral separation media for HPLC of enantiomers. The mode of selector linkage, length and chemistry of the tethering arm, and nature of the underlying support were investigated to enhance the performance of polymeric chiral stationary phases (CSPs).; Two general combinatorial methods for enantiomer recognition are also introduced and applied for a rapid preparation of novel CSPs useful in HPLC. First, libraries of chiral selectors are immobilized on size monodisperse porous organic polymer beads and the so obtained chiral stationary phases tested in the separation of a racemic target analyte. Further deconvolution of the libraries affords an optimized CSP. In the second approach, a library of racemic selectors is prepared in solution and screened with a CSP containing the enantiomerically pure target analyte. Both methods enable a fast evaluation of libraries to discover an efficient chiral selector.