Pushing the miniaturisation of LC with shear-driven flows

Recently, a novel driving principle for the mobile phase flow in open-tubul ar chromatographic systems has been proposed to evade the pressure drop lim itation of pressure-driven chromatographic systems. The concept, further re ferred to as shear-driven chromatography (SDC), gives hitherto unachievably large mobile phase velocities through channels with a sub-micron thickness . Applying the SDC-concept in channels with a flat rectangular cross-sectio n (e. g., 100 micrometer wide and only a few hundred nanometer thick), we h ope to combine the high separation speed and resolution offered by the smal l channel thickness with a sufficient mass loadability arising from the lar ge channel width. An attractive feature of the concept is furthermore that all the mobile and stationary phases of conventional LC can be used without any restriction or modification. The concept hence also provides a powerfu l alternative to CEC. In the present paper, we first focus on some of the theoretical advantages of SDC and we then subsequently present the first series of peak broadening measurements in shear-driven micro-channel flows. These experiments show g ood agreement with the theoretical expectations and hence represent a (part ial) demonstration of the practical realisability of the SDC-concept.