LIQUID ADSORPTION CHROMATOGRAPHY WITH MIXED MOBILE PHASES .3. INFLUENCE OF MOLECULAR AREAS OF SOLVENTS AND CHROMATOGRAPHED SUBSTANCES ON THE CAPACITY RATIO

A new equation for the capacity ratio in liquid adsorption chromatography with a two-component mobile phase, involving the differences in molecular areas of solvents and chromatographed substances, has been derived. The special case of this equation is the logarithmic relationship of Snyder and Soczewiński, which is frequently used for describing the dependence of the capacity ratio on the composition of the mobile phase. According to our treatment the relationship of log (capacity ratio) to log(ratio of mole fractions of the more efficient solvent in the stationary and mobile phases) is linear for liquid mixtures by unit activity coefficients. This dependence has been examined by using thin-layer chromatographic data and excess adsorption isotherm for the binary solvent mixture. The excess adsorption data were used to calculate the mole fractions of the more efficient solvent in the stationary phase for different compositions of the mobile phase. © 1979.