High-resolution liquid chromatographic separations in 400 nm deep micro-machined silicon channels and fluorescence charge-coupled device camera detection under stopped-flow conditions Original Research Article

We report on a study exploring the possibilities of silicon etched, flat-rectangular nano-channels for the acceleration of liquid chromatography separations. Using the shear-forces originating from a moving channel part to propagate the mobile phase flow, a mixture of two neutral coumarin dyes could be separated in less than 50 ms and with a resolution of over N=106 plates/m. The obtained experimental van Deemter-plot show a good agreement with the theoretical expectations and has a minimal plate height around H=1.0 μm (k=1.5) and H=0.6 μm (k=0.5). The different steps in the fabrication of the nano-channels, and the advantages of a novel detection scheme, based on fluorescent charge-coupled device-array imaging under stopped-flow conditions, are discussed as well.