| Recent studies in the literature have suggested that the A term in the equation for the plate height, which is the term accounting for interparticle dispersion, is more significant, and may largely determine the column performance in a variety of preparative and analytical high-performance chromatographic processes. In this study, we developed a complete theory for the A term by first defining two ideal regimes, which are the close to equilibrium and far from equilibrium regime, as well as the intermediate regime based on an extension of a result obtained by Wang and Stewart result. The interparticle dispersion in a chromatographic column are studied experimentally and theoretically using HPLC columns containing micropellicular (nonporous) particles so that intraparticle mass transfer is eliminated as a plate height contribution. Single and bi-directional plate height experiments were performed, as well as arrested flow experiments where the 2D band shape in the column was visualized. By using this combined experimental and theoretical approach, our study provided a rigorous foundation for the transcolumn contribution to the plate height, and also a better understanding of the connection between the column packing processes, the structure of a packed chromatographic bed, and the performance of a chromatographic column. |
