Packing material, superficially porous

The use of column with superficially porous packing materials based on silica particles with nonporous cores is the most recently reported strategy for improving chromatographic performance. This technology, originally developed by Kirkland in the 1990s to limit diffusion of macromolecules into the pores [85], became commercially available in 2007 [86], In comparison with totally porous particles of similar diameters, the both A and C term of the Van Deemter curve are reduced [87, 88],... [Pg.375]

Porous Media Packed beds of granular solids are one type of the general class referred to as porous media, which include geological formations such as petroleum reservoirs and aquifers, manufactured materials such as sintered metals and porous catalysts, burning coal or char particles, and textile fabrics, to name a few. Pressure drop for incompressible flow across a porous medium has the same quahtative behavior as that given by Leva s correlation in the preceding. At low Reynolds numbers, viscous forces dominate and pressure drop is proportional to fluid viscosity and superficial velocity, and at high Reynolds numbers, pressure drop is proportional to fluid density and to the square of superficial velocity. [Pg.665]