Study on partition of D(-)-mandelic acid in aqueous two-phase systems

Studies on the partition of D(-)-mandelic acid were performed in poly(ethylene glycol)(PEG) with molecular masses of 2000, 4000, 6000, 10000, 20000-ammonium sulfate systems. The effect of various parameters such as molecular mass of PEG, phase composition, pH of the system, temperature and NaCl concentration were investigated in this work. Molecular mass of PEG is a key factor affecting the partitioning behaviors of D(-)-mandelic acid in the PEG-(NH4)(2)SO4 systems. Influence of pH on partition shows that the partition coefficients of D(-)-mandelic acid decrease with the increase of pH value. D(-)-mandelic acid partition is only slightly influenced by the temperature. For the PEG6000-ammonium sulfate systems, the addition of NaCl increases the partition coefficient of the D(-)-mandelic acid significantly. All these indicate that the aqueous two-phase is a very suitable alternative system for the separation of D(-)-mandelic acid.