Polymer-brush stationary phases for open-tubular capillary electrochromatography.
Synthesis of poly(2-hydroxyethyl methacrylate) (PHEMA) brushes from the inside of silica capillaries by surface-initiated atom transfer radical polymerization (ATRP) yields unique stationary phases for open-tubular capillary electrochromatography (OT-CEC). Although PHEMA brushes have only a small effect on the separation of a set of phenols and anilines, derivatization of PHEMA with ethylenediamine (en) allows baseline resolution of several anilines that co-elute from bare silica capillaries. Derivatization of PHEMA with octanoyl chloride (C8-PHEMA films) affords even better resolution in the separation of a series of phenols and anilines. Increasing the thickness of C8-PHEMA coatings by a factor of 2 enhances resolution for several solute pairs, presumably because of an increase in the effective stationary phase to mobile phase volume ratio. Thus, this work demonstrates that thick polymer brushes provide a tunable stationary phase with a much larger phase ratio than is available from monolayer wall coatings. Through appropriate choice of derivatizing reagents, these polymer brushes should allow separation of a wide range of neutral molecules as well as compounds with similar electrophoretic mobilities.
Miller
Matthew D
MD
Department of Chemistry, Michigan State University, East Lansing, MI 48824-1322, USA.
Baker
Gregory L
GL
Bruening
Merlin L
ML
D020374:Chromatography, Micellar Electrokinetic Capillary / Q000295:instrumentation*; D011102:Polyhydroxyethyl Methacrylate / Q000138:chemical synthesis / Q000737:chemistry*
D011102:Polyhydroxyethyl Methacrylate