Simulation and experimental study of the transport of protein bands through cuboid packed-bed devices during chromatographic separations

Recent studies have demonstrated that box-shaped or cuboid packed-bed chromatographic devices represent an efficient alternative to conventional cylindrical columns for high-resolution preparative protein separations. This has been attributed to the greater uniformity of flow within these devices. However, for a more complete explanation, it is important to understand how the system hydrodynamics affects band broadening during the transport of proteins through these devices. In this study, we present first principle mathematical models to capture this interplay. These models were validated by flow-through and bind-and-elute experiments carried out using a colored protein as tracer. Control experiments were also carried out using equivalent commercial columns, i.e. having same bed height and cross-sectional area, and packed with same media. The trends observed in the experiments matched those predicted by the models, though there were deviations in the absolute values. These deviations are explained in terms of non-idealities that exist in the experimental set-up, as well as in terms of factors that were not considered in the model. The models discussed in this paper are not only useful for understanding the workings of the cuboid packed-bed device, but are also useful tools for designing, optimizing and scaling-up such devices.