NEW DISPLACEMENT TECHNIQUE FOR PREPARATIVE LIQUID-CHROMATOGRAPHY

A new hybrid displacement technique (patent pending) for separating mi xtures which incorporates the positive aspects of displacement chromat ography and sample self-displacement, has been developed. Immediately after injection of the separation mixture, a relatively large, but fin ite amount of an inert material is injected onto the column to act as a ''displacing compound''. The purpose of this displacing compound is to drive the separation by providing additional adsorption site compet ition, thus enhancing the displacement effect. It functions to help ma intain the concentrations of the actual separation components so that tailing and/or fronting, yield limiting factors in sample self-displac ement, are mitigated. The displacing compound is distinct from a true displacer because it is introduced in a limited quantity at the outset of the separation, not as a continuous additive. Feasibility has been demonstrated and operational parameters investigated. Using a displac ing compound sharpens zone boundaries between mixture components. The practical significance of this effect includes increased loading capab ility and the ability to achieve high yields when the major component elutes first. The impact of adding a displacing compound is greater wh en the separation factors (alpha) between the mixture components are s maller.