High-performance liquid chromatography pressure drops

High-Performance Liquid Chromatography. The difference between classical LC and HPLC can be explored by referring to Figures 21.13 and 21.14. For classical LC, large porous particles with dp = 100-250/ m (Fig. 21.13A) are packed into columns with internal diameters of 1-5 cm (Fig. 21.14A). Little pressure is required to permit slow solvent flow between these large particles. Normally, a small head of liquid in the column above the surface of the packing or, in some cases, a reservoir container connected to and placed above the column acts as the constant-pressure source. Pressure drops are of the order of 0.1-1 atmosphere. Flow rates are very... 

While we have only focused here on applications for DNA electrophoresis, colloidal crystals have also been used as a stationary phase for separating hydrophobic dyes and proteins [40]. The arrays may prove especially interesting for electrophoretic protein separations, since the pore size provides a steric constraint, no pressure drop is required for transport through the small pores and the bead surfaces serve as a substrate for reversed-phase adsorption. These arrays thus offer a tunable variety of separation mechanisms. Indeed, proteins with similar hydrophobic groups, which cannot be separated by high performance liquid chromatography (HPLC) due to their similar adsorption properties, are rapidly separated by charge in colloidal arrays [40]. 

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