Macroporous polyacrylamide poly(ethylene glycol) matrixes as stationary phases in capillary electrochromatography

A one-step method is described for in situ preparation of macroporous polymeric matrixes to be used as stationary phases for capillary electrochromatography. The monomers (acrylamide, bisacrylamide, and acrylic or vinylsulfonic acid), including hydrophobic ligands (C-4, C-6, or C-12), and poly(ethylene glycol) have been polymerized in formamide (or N-methylformamide) aqueous solutions inside the capillary. The capillary nail had been activated first by a bifunctional recent, to couple covalently the resulting gel inside the fused-silica tubing, Thus, no frit is necessary to keep the stationary phase in place. High efficiencies were obtained for a mixture of alkyl phenones (up to 398 000 plates/m). Good separations are achieved in less than 5 min. The migration time reproducibility is better than 1% (RSD) from run to run and 2.5% from day to day. The gel is stable up to at least 50% acetonitrile used as a mobile phase. On-column UV and fluorescence detection can readily be employed. Applications to peptides and carbohydrates are also shown.