Characteristics of octadecylsilylated silica gels end-capped by high-temperature silylation

Abstract Octadecylsilylated silica gels (ODSs) that were end-capped by high-temperature silylation (HTS) were shown to be effective in the elimination of the undesirable secondary interaction with chelating compounds. ODSs prepared from high-purity or low-purity silica gel treated with HCl, or untreated, were end-capped by HTS or by liquid-phase silylation. ODSs that were end-capped by HTS and prepared from high-purity silica gel treated with HCl showed little secondary interaction with chelating compounds. The secondary interaction with pyridine was eliminated by HTS, regardless of the purity of the base silica. HTS also improved the stability of packing material at high pH, by reducing the dissolution rate of the base silica, and prevented hydrolysis of the bonded phase at low pH values.