Surface Modified Silica Gels as Porous Material for GPC

Authors:
  • KUK. Unger
    K. Unger
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Abstract
The separation efficiency of GPC columns filled with porous silica gel is influenced by adsorption effects leading to an additional peak broadening of the elution curve. To study this effect silica gel was prepared in the form of totally spherical particles. Two portions of the same material were modified yielding a dense monolayer of phenyl- and methyl-groups, respectively, chemisorbed on the surface. The pore size distribution of the samples remained unchanged by the surface reaction. The adsorption of dissolved polystyrenes on these three species investigated under static conditions showed a small decrease from the original to the phenylated sample. Negligibly small adsorption was observed for the methylated sample. Under GPC conditions using three columns filled with each silica gel species the same decrease in the standard deviation σ of the elution peaks of dissolved polystyrenes was observed.