Preparation of uniformly sized polymeric separation media potentially suitable for small-scale high-performance liquid chromatography and/or capillary electrochromatography

Uniformly sized polymer particles were prepared by either a two-step swelli ng and polymerization method or a Shirasu porous glass (SPG) emulsification technique to compare their suitability as a uniformly sized packing materi al for small-scale high-performance liquid chromatography (HPLC) or capilla ry electrochromatography (CEC). The SPG emulsification technique afforded s lightly worse size uniformity compared to the two-step swelling and polymer ization technique. However, fairly nice spherical shapes with reproducible outward appearance and internal pore size distribution were obtained for bo th of 3- or 6-mu m sized particles. On the other hand, the two-step swellin g and polymerization method afforded broken particles with quite different outward appearances due to the polymeric porogen effects of seed polymer ut ilized as the shape template. In HPLC, the column packed with the 3-mu m pa rticles prepared with the SPG emulsification technique proved to have a fai rly high column efficiency with good column stability, as assessed under re peated use in gradient elution. On the other hand, the column packed with t he packing material obtained through the two-step swelling and polymerizati on method showed much poorer column stability, while initial column efficie ncy was compatible to that obtained using the SPG emulsification method. In addition, the packing material prepared with the SPG emulsification techni que could be modified with ion-exchangeable monomers and showed fairly good column efficiency in the CEC mode. (C) 1999 Elsevier Science B.V. All righ ts reserved.