[Prediction of eluotropic sequence of solutes in countercurrent chromatography]

According to the retention equation of countercurrent chromatography (CCC), the eluotropic sequence of solutes depends mainly on the order of their partition coefficients between the two immiscible liquid phases. The varying tendencies of partition coefficients of some compounds in aqueous or non-aqueous solvent systems by calculating the phase equilibria with universal quasichemical functional group activity coefficient (UNIFAC) (Dortmund) model are predicted. These compounds included saturated and unsaturated fatty acids ethyl esters, N-2,4-dinitrophenylamino alcohols, p-nitrophenyl glucosides and so on, with simple structures and much differences in polarity. It has been found that the predicted tendencies of partition coefficients of the analogues were consistent with the experimental ones reported in literature, and the best results were obtained for saturated fatty acid ethyl esters in hexane-acetonitrile (1:1 in volume ratio) solvent system. The establishment of a method for prediction will be helpful for the selection of non-electrolyte solvent systems in CCC.