Scale up in preparative chromatography

The subject of the paper is the application of a theoretical concept to scale up preparative chromatography. As an experimental example, the separation of the alpha- and beta-isomers of a steroid compound using silica as the stationary phase is discussed. The applied concept is mainly based on measuring the adsorption isotherms in preliminary investigations using an analytical column. With these thermodynamic parameters it is attempted to simulate the separation behaviour in larger columns using the equilibrium dispersive model. To check the accuracy of the approach, experimental studies have been carried out using three other columns with increasing diameters (0.8, 5 and 30 cm). On the basis of the determined adsorption isotherms and a phase ratio adjustment, the main features of the separation process can be predicted for the larger columns. Thus, the presented concept can be effectively used in the process of optimizing preparative chromatography.