Chromatography displacement development

Modes of Operation The classical modes of operation of chromatography as enunciated by Tisehus [Kolloid Z., 105, 101 (1943)] are elution chromatography, frontal analysis, and displacement development. Basic features of these techniques are illustrated in Fig. 

Displacement Development A complete prediction of displacement chromatography accounting for rate factors requires a numerical solution since the adsorption equilibrium is nonlinear and intrinsically competitive. When the column efficiency is high, however, useful predictious can be obtained with the local equilibrium theoiy (see Fixed Bed Transitions ). 

A chromatographic separation can be developed in three ways, by displacement development, by frontal analysis, and by elution development, the last being almost universally used in all analytical chromatography. Nevertheless, for the sake of completeness, and because in preparative chromatography (under certain conditions of mass overload) displacement effects occur to varying extents, all three development processes will be described. 

Tiselius, A. Developed liquid chromatography and pointed out frontal analysis, elution analysis, and displacement development. 

Claesson, S. Liquid-solid chromatography with frontal and displacement development analysis. Co-worker A. Tiselius. 

For separations involving large amounts of Am, Cm, or rare earths, displacement development provides a satisfactory first-cycle separation and yields Am and Cm products and a transcurium element fraction suitable for final separation by elution development. However, alternative methods for the first cycle (removal of the bulk of the lighter actinides and rare earths) are available besides displacement development chromatography, these include solvent extraction and the LiCl-anion exchange system. 

Fio. 5.—Chromatography on Carbon (Carboraffin Supra) of a Mixture of n-Glu-cose, Sucrose, and Raffinose by Displacement Development with 0.5% Ephedrine in Water (Refractive Index vs. Volume of Developer). ... 

Experimental work of Kalasz et al. resulted in the statement of the characteristics and basic rules of displacement chromatography. They conceived properties of the fully developed displacement train, factors affecting displacement development, efficacy of separation, analysis of displaced fractions, determination of displacement diagrams from Langmuirian isotherms, as well as selection of the column, carrier, and displacer for displacement chromatography. Concentration of the sample is a particular feature of displacement chromatography. However, the displacer in the carrier is also definitely concentrated through the development of the displacement train. 

In 1940, Tiselius [14] classified chromatography according to the separation principle, namely, elution development, displacement development and frontal analysis. In practice only elution and to a lesser extent, displacement development are commonly used (Figure 1.3, p. 13). 

Tswett recognized the difference between elution and displacement development, although Tiselius was the first to clearly define these differences. While displacement was popular in the 1940s, that popularity waned in the 1950s. In the 1980s, there was a resiugence of interest in displacement operation due to the efficient utilization of the stationary phase possible in that mode. Frenz and Horvath have pubhshed a comprehensive review of the history and applications of displacement chromatography. 

In principle, the modes and steps in preparative chromatography do not differ from those in analytical chromatography. Four modes are used (Fig. 4) isocratic elution, linear gradient elution, stepwise elution, and displacement development. Frontal analysis is not used for purification of biomolecules, but it is used for... 

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