Surface initiated molecularly imprinted polymer films: a new approach in chiral capillary electrochromatography

A new generation of imprinted composite particles was tested as capillary e lectrochromatography stationary phase. Silica particles characterised by a well defined particle size (10 mum diameter), shape and pore system (1000 A ngstrom) were modified with an azoinitiator and subsequently used to graft molecularly imprinted polymers targeted to bind L-phenylalanine anilide. Fu sed silica capillaries were packed over a length corresponding to 8 cm, usi ng a pneumatic amplification pump, and the stationary phase thus obtained w as tested with respect to its electrochromatographic performance. The elect roendosmotic flow mobility was evaluated with respect to both the different content of polymer on the silica particle surface and different operating pH values. The dependence of various parameters, namely the analyte concent ration, the polymer layer thickness and the pH of the mobile phase on the e nantioselectivity was investigated. These CEC capillaries showed enantiosel ectivity comparable with that showed in LC, and exhibited improved performa nce in terms of plate number N-1 ( similar to 13 000), selectivity alpha ( similar to 1.5), analysis time ( < 3 min), inter-intraday and intercapillar y reproducibility. We expect this approach to result in a new generation of robust, tailor-made chiral or affinity stationary phases for CEC.