Modeling of Liquid Chromatography with Cored Beads

Abstract

In typical LC operations, the Biot numbers for mass transfer are much larger than 2. This means intraparticle diffusion is typically the limiting step, while interfacial film mass transfer between the bulk-fluid phase and the particle phase is relatively fast. Due to its spherical structure, the center section of a particle has a disproportionately small volume, but it presents a relatively large radial distance for diffusional mass transfer. To the other extreme, nonporous beads offer no intraparticle diffusion due to a lack of macropores. These beads have found success in fast analytical LC that uses very small sample sizes. In the absence of intraparticle diffusion, they offer sharp peaks [1, 2]. However, they have insufficient binding sites per unit volume without the macropores and thus they are unsuitable for preparative- and large-scale LC.