Parallel separations in microfabricated channels with capillary electrophoretic sample introduction

摘要

We have developed a method to carry out small-scale electrophoretic separations by coupling electrophoresis in a capillary to electrophoressis in a narrow rectangular channel. This format allows rapid sequential separations or continuous analysis to be carried out on small-volume samples and with efficient heat dissipation. This approach has been developed for dynamic sampling of picoliter microenvironments (i.e., solution around single cells). Separations in 8-mum thick channels with electrochemical array detection provide low femtomole detection limits for separated catecholamines. We have also demonstrated separations in 0.6-mum channels and work with 0.2-mum channels is planned. The long-term goals of this methodology include continuous separations with sub-second thime resolution, development of attomole detection limits, and new separation modes in these extremely narrow structures. Another goal of this work is to use this separation format to introduce and separate large numbers of DNA samples in parallel. Both of these goals require limiting the lateral spreading in the channel and, hence, we have developed channels with microlithgraphically defined partitions.