High-speed electroseparations inside silica colloidal crystals

Crystals made from 200 nm silica colloids are hardened and chemically modified with chlorodimethyloctadecylsilane for use in electrically driven, reversed-phase separations. A van Deemter plot reveals extremely narrow peak widths for the separation of a cationic hydrophobic dye, DiI, with both the A and C terms 10-fold smaller than those for a conventional HPLC column. Electrically driven separations are demonstrated to be achieved in less than 10 s for three dyes differing in hydrophobicity and also for three peptides differing in electrophoretic mobility. The results show that these media are promising for high-speed separations.