Adsorption from binary solvent mixtures onto silica gel by HPLC frontal analysis

Summary The chromatographic technique of frontal analysis is applied to measuring adsorption from binary liquid mixtures by silica gel. The complete adsorption isotherm of a solvent mixture is obtained by measuring the break-through curves for a series of small concentration steps of the mobile phase. This method offers a direct way to determine the composition of the stationary phase in liquid-solid chromatography with mixed mobile phases. The surface excess isotherms of all binary systems formed by benzene, cyclohexane, and 1,2-dichloroethane, at the solution-silica gel interface at 25 °C are presented. The data of the three systems are shown to be thermodynamically mutually consistent.