RETENTION BEHAVIOUR IN HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY ON THREE TYPES OF OCTADECYL MODIFIED COLUMN GELS USING HEAT-TREATED SILICAS BY CALCINATION

Abstract

The effect of silanol groups on heat-treated silicas by calcination has been studied by high-performance liquid chromatography. After heat-treating at various temperatures, the silicas were used for the measurement of physical parameters and chemical analysis. After heat-treating at 180°C, the reactive silanol group concentration on the silica treated with octadecyldimethylchlorosilane was determined to be 2.0 per 100Ų(1nm²) from elemental analysis data for carbon (original silica: mean pore diameter 116Å, specific surface area 298m²/g, pore volume 1.22ml/g, particle size 5.0μm). Similarly the reactive silanol group concentration on the silica treated with hexamethyldisilazane was determined to be 2.4per 100 Ų³(1nm²). On the basis of the physico-chemical and chromatographic data the heat treated silicas by calcination have been compared.