TWO-STEP MODIFICATION OF SILICA TO OBTAIN ENERGETICALLY HOMOGENEOUS CHROMATOGRAPHIC SORBENTS

We have carried out a two-step liquid-phase modification of amorphous silica Silokhrom-80 with polyethyl hydride siloxane and hexamethyldisilazane. Using the parameters of the Langmuir equation, we have determined the concentration of residual hydrophilic sites on the surface of the modified silica, and we have identified them. We have shown that two-step modification of silica by selected reagents makes it possible to completely deactivate the most active vicinal hydroxyl groups on the sorbent surface, and to deactivate its isolated hydroxyl groups to a significant extent.