Prediction of Plate Height Curves of Porous-Shell Pillar Array Columns Micro-Pillar Array Columns.

We investigate band broadening in the most widely adopted configuration of micro-pillar array columns (μ PACs)—specifically, a cylindrical pillar array where both the pillar walls and the channel bottom are coated with a thin layer of mesoporous material. The two-zone moment analysis method is adopted to investigate the dispersion properties of μ PACs in a broad range of shell thicknesses, reduced fluid velocities, and retention factors. Three different models of the unit cell, of increasing complexity, have been implemented, namely a two-dimensional model and two different three-dimensional models with and without the retentive bottom layer, the presence of which seems to have a very significant effect on the plate height curves. Model predictions are compared with experimental van Deemter curves for uncoated and coated porous layers, and a robust relationship between the intra-particle (porous-zone) diffusion coefficient D pz and the retention factor k ′ is established. [ABSTRACT FROM AUTHOR]