The influence of the non-homogeneity of the silica support and the nature and amount of modifier employed on the adsorption properties of materials with chemically bonded amino and guanidino groups was studied by means of gas chromatography (GC), adsorption measurements under static conditions and IR spectroscopy. The results indicate that adsorbents coated with a polymer film of amino groups have a nearly uniform surface. These adsorbents can be used for GC investigations and for the separation of polar compounds, including organic bases.

The adsorption properties of silica gel with grafted aminopropyl and guanidinoethanethiol (GET) groups were studied by the techniques of adsorption under static conditions and gas chromatography. It was shown that molecules capable of forming hydrogen bonds are adsorbed on all modified samples more weakly than on the initial silica gel. The grafting of GET radicals on the surface results in a noticiable increase in the dispersion interaction with adsorbed molecules. Calculation of the contributions of molecular groups to the constant of adsorption equilibrium showed that the thermodynamic characteristics of adsorption on aminosilochromes and aminosilicas with a polymeric layer of the modifying agent have similar values. Such adsorbents can be used for investigation of polar compounds, including organic bases.