CHARACTERISTICS OF OCTADECYLSILYLATED SILICA-GELS END-CAPPED BY HIGH-TEMPERATURE SILYLATION

Octadecylsilylated silica gels (ODSs) that were end-capped by high-tem perature silylation (HTS) were shown to be effective in the eliminatio n of the undesirable secondary interaction with chelating compounds. O DSs prepared from high-purity or low-purity silica gel treated with HC l, 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 chelati ng compounds. The secondary interaction with pyridine was eliminated b y HTS, regardless of the purity of the base silica. HTS also improved the stability of packing material at high pH, by reducing the dissolut ion rate of the base silica, and prevented hydrolysis of the bonded ph ase at low pH values. (C) 1998 Elsevier Science B.V. All rights reserv ed.