Silane-based copolymers as chromatographic stationary phases

In this work, a group of thermally stable polar-embedded polymer based stationary phases are presented. The silane-based copolymer is synthesized by radical polymerization to incorporate polar groups, through phenylmaleimides, and alkoxysilane groups. By way of the alkoxysilane groups, the copolymer can be attached on to silica particles or converted to polymer-silica composite particles using tetraethoxysilane (TEOS) as a sol-gel precursor. Through characterizations in this work, they proved to be stable in high temperatures (400°C) as well as effective in high water mobile phases. Phenyl moieties of the material provide increased and sometimes excessive retention of analytes with pi-systems occurred in many of the separations. By manipulating the functional groups add to the maleimide, chemical selectivity can be controlled by the difference in polarity. With the halogen-modified maleimides, peak shape was improved in the basic solutes in the reduction of band fronting and tailing. Also, increasing the column temperatures reduced band broadening as well as decreasing retention of the most retained peaks. Results lead to the conclusion that these polar-embedded stationary phases would be of good use in subcritical water chromatography