Sub-second liquid chromatographic separations by means of shear-driven chromatography

Peer Reviewed: Shear-Driven Flow Approaches to LC and Macromolecular Separations

“…Figure 2 illustrates the case in which the channel spacers are etched along the entire width of a silicon wafer. The 4 central dark lines on the silicon wafer represent the 350-µm-wide channel spacers (20,24) etched along the entire width of the wafer and enclosing 3 adjacent, parallel separation channels, each of which is 700 µm wide (Figure 2a). The two outer dark lines represent two additional spacers added to improve stability.…”

“…To eventually obtain the small plate heights and short separation times predicted by SDF theory, we tried numerous experimental setups (20,21,23,24,31). The separation was conducted at a velocity below the optimal mobile-phase velocity, u opt , because the scan rate of the CCD camera (52 frames/s) was too slow to follow separations that are <0.1 s, which can be obtained when mobile-phase velocities are in the centimeter-per-second range.…”

Generation of mass tags by the inherent electrochemistry of electrospray for protein mass spectrometry

“…For example, analytical separations such as capillary electrophoresis (CE) [3,4], two-dimensional electrokinetic separations [5], liquid chromatography (LC) [6], reaction and detection microchambers [7][8][9] have been implemented in the microfluidic format. More recently, analytical microfluidic systems have caught interest in the particular field of proteomics [10,11] because of the high analytical constraints demanded by this field, namely the low amount of sample usually available, the high complexity of the initial protein mixture, and the need for high-throughput analysis [12].…”

A novel microstep device for the size separation of cells

“…To inject the cell and particle samples, the same multistep injection procedure as originally developed for our small molecule experiments [22] has been used. This procedure occurs in four successive, semiautomated steps.…”

“…This so-called shear-driven flow principle can be used to enhance the speed and resolution of a variety of microfluidics applications such as on-chip liquid chromatography (LC) [22][23][24], DNA microarray screening [25], and target-receptor binding kinetics measurements. The major advantage of shear-driven flows is that the applicable fluid velocity is independent of the fluid viscosity and the channel depth and length, hence completely avoiding the limitations on the applicable flow velocities existing in pressure-and electrokinetically driven nanochannels.…”