Adsorption columns, residence time distribution

Any chromatographic technique is based on the flow through a porous medium— the stationary phase. The flow in the pores is very slow and the transport of solutes and particles is mainly diffusive. Adsorption/desorption, hydrodynamic or steric effects specifically influence the residence time of the different species and, thus, facilitate their separation. In SEC, one employs stationary media with very hroad pore size distributions. Since the particles can only move into those pores that exceed their geometric dimensions, the penetrable pore volume decreases with increasing particle size. Coarse particles, therefore, pass the column more quickly than fine ones (Fedotov et al. 2011). SEC was originally developed for the separation of polymer... 

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