A microfabricated fluidic device for performing two-dimensional liquid-phase separations

A microfabricated fluidic device that combines micellar electrokinetic chro matography and high-speed open-channel electrophoresis on a single structur e for the rapid automated two-dimensional analysis of peptides has been dev ised and demonstrated. The microchip operates by rapidly sampling and analy zing effluent in the second dimension from the first dimension. Second-dime nsion analyses are performed and completed every few seconds, with total an alysis times of less than 10 min for tryptic peptides. The peak capacity of the two-dimensional separations has been estimated to be in the 500-1000 r ange. The orthogonality of the separation techniques, an important factor f or maximizing peak capacity or resolution elements, was verified by examini ng each technique independently for peptide separations. The two-dimensiona l separation strategy was found to greedy increase the resolving power over that obtained for either dimension alone.