Porogen imprinting effects

It is shown that macroporous, cross-linked polymer stationary phases for HPLC should memorize shape or size of the porogen utilized in the polymerization step to afford preferential retention of the solute utilized as porogen in HPLC. The polymer stationary phase prepared using o-xylene or p-xylene clearly affords the longest retention of the solute utilized as the porogen, and other solutes having molecular size or shape similar to that of the porogen also tend to be preferentially retained. The observed molecular recognition ability is very stable, even after heat treatment of the particles up to 200 degrees C, and and effect of the loaded volume of solutes on the retentivity is almost neglible. H-u plots suggest that mass transfer of the solute utilized as the porogen within the polymer particles is comparatively slower than those of other solutes.