Operating mode selection for the separation of intermediately-eluting components with countercurrent and centrifugal...

Two operating modes that can be used for the separation of intermediately-eluting target components from complex mixtures using solid support-free liquid-liquid chromatography (LLC) include batch injections and trapping multiple dual mode (trapping MDM). Batch injections offer the advantage of simpler equipment and process design, while the trapping MDM process, although more complex, can provide improved resolution at low separation factors. In this study, a thorough comparison of batch injection and trapping MDM performance with respect to productivity is made using simulations for a wide range of separation tasks (target component/impurity separation factors; minimum purity and yield requirements). For each separation task, the maximum productivities obtained by the two operating modes were separately determined with respect to their independent parameters. The results indicate that trapping MDM can be used to extend the application of LLC down to separation factors as low as 1.1, with its use being most advantageous for separation factors of approximately 1.3. However, the simpler batch injection process remains preferable for separation factors around or greater than 1.5.