HPLC STUDY OF THE ADSORPTION FROM SOLUTIONS ON 2 SILICA-GELS

In this paper, we report and discuss the adsorption isotherms of hydro -organic mixtures and of compounds used as mobile phase in reversed ph ase and normal phase high performance liquid chromatography (RP-HPLC a nd NP-HPLC, respectively). This work is the first attempt to study the solid-liquid interface between two types of chromatographic silica su rfaces and pure organic adsorbates from water and from organic eluents by HPLC. Frequently, among the dynamic techniques the method of choic e for the measurement of an adsorption isotherm is frontal analysis. W e suggest here the combination of the technique based on peak asymmetr y calibration and peak profiles, which allows calculations directly fr om integration data. The group of systems studied permits the analysis of the intermolecular interactions on the silica surface. Particular attention was given to the system methanol-water and the measurement o f the adsorption of n-octanol from methanol on RP-silica was also carr ied out.