Optimization displacement chromatography

The development of displacement separations has historically been an empirical process and even though chromatographic theory may guide the selection of operating conditions the final stage must involve experimental validation. Typically, several experiments will be carried out at or near the conditions determined by the theory. The final stage in the procedure is either experimental or numerical optimization of the displacement process to produce optimal yields, purities and productivities. At this point, the relative efficacy of selective and conventional displacement chromatography can also be evaluated. 

Felinger, A., Guiochon, G., Optimization of the experimental conditions and the column design parameters in displacement chromatography, J. Chromatogr. A, 1992b, 609, 35. 

The optimization of the experimental conditions in displacement chromatography for maximiun production rate has been studied less than the optimization of overloaded elution, reflecting the lesser importance of this method in industrial practice. Frenz et al [52] performed an experimental study of the dependence of the throughput on the operational parameters in reversed-phase displacement systems. They demonstrated that both the nature and the concentration of the displacer must be appropriately selected to optimize the throughput. Jen and Pinto [53] have used the ideal model, and the fe-transform approach to maximize... 

The production rate is much higher in elution than in displacement chromatography if the retention factor has been optimized. If a large value of the retention factor is used, as is conventionally done, the production rates achieved with both modes are comparable. 

Phillips, M. W. Subramanian, G. Cramer, S. M. "Theoretical optimization of operating parameters in nonideal displacement chromatography" J. Chromatography. 1988, 454, pp 1-21. 

A drawback of displacement chromatography is the fact that optimum conditions cannot be found by scaling-up of analytical methods." However, after a successful but more or less time-consuming optimization of the displacement system, no other method allows this high throughput per unit time with this low consumption of the mobile phase. 

As is common to all affinity chromatography protocols, only the desired protein is supposed to bind to the column. The target protein then has to be eluted off the column, in this case with 0.5 m imidazole which displaces the imidazole rings of the histidine residues of the target protein. Non-specific binding is often observed, which results in several intermittent washing steps being required as well as optimization of the protocol for each protein. 

---