Bonded Polymethacrylate Stationary Phases for Open Tubular Liquid Chromatographic and Electrochromatographic Separations

Using a new procedure developed in our laboratory for the preparation of thick polymethacrylate films bonded in fused silica capillaries, crosslinked polymeric stationary phases were synthesized in situ in 25-mm-i.d. capillaries. The effect of monomer and crosslinker concentrations on the resulting polymer film Ž . was studied by open tubular capillary electrokinetic chromatography OTCEC Ž . using p-hydroxy benzoates parabens as test solutes. Retention of analytes showed interesting trends versus monomer and crosslinker concentrations, exhibiting maxima at certain combinations rather than a continuous increase in capacity factor with increasing concentration. Because the electroosmotic flow can arise from both exposed silica and polymer surfaces, the flow velocity did not exhibit an obvious trend versus monomer andror crosslinker concentration. Open tubular liquid Ž . chromatographic OTLC separations were also achieved using head pressure as the driving force for bulk flow, without employing a high-voltage power supply or micro LC pump. Q 1998 John Wiley & Sons, Inc. J Micro Sep 10: 99]105, 1998