Displacement Development:

Displacement development has the advantages of being able to accommodate large samples and providing sharp separations. That depends on the competition among solutes for the active sites of the adsorbent and is only really effective in separating very strongly adsorbed materials. Within displacement development, all the substances in the sample will be held on the stationary phase so strongly in which they cannot be eluted through the mobile phase; they can, nevertheless, be displaced by substances that are held on the surface by stronger forces. Therefore, there will be competition among individual solutes and, when the sample is placed on the column, all the immediately available active sites of the adsorbent will be occupied by the most strongly held component.

As the band of the sample moves down the column, next available sites will be occupied through the next strongly retained component. Thus, all the components array themselves along the column in order of their adsorption strength. To develop the chromatogram, another substance called the displacer is introduced into the mobile phase stream; the displacer has an even higher affinity for the adsorbent than any of the components to be separated.