SOLVENT CONCENTRATION-DEPENDENCE OF SOLUTE DISTRIBUTION COEFFICIENT

A simple method for modeling the solvent concentration dependence of s olute distribution coefficient is described. Ideal and modified distri bution models are proposed based on the mechanism of multicomponent co mpetitive adsorption and the theory of solvent association. The system cresol-methanol/water-beta-CD-silica is tested using the models, whic h compared with other experimental results show that the ideal distrib ution model fails at higher water concentrations and that the modified model can describe well the observed solute distribution behavior ove r the entire concentration range. The relative impact of nonideal fact ors in the adsorbed phase and the solvent association in the mobile ph ase on the distribution dependence shows that the limitation of the id eal model at higher water concentrations results mainly from uneven sa turation capacities of the solute and solvent components for the syste m studied here.