Stationary phase type and temperature effect on HPLC separation of lactic acid enantiomers

Lactic acid is a biologically important organic acid existing in two enantiomeric forms which are differently metabolized in the human body. In this paper, direct chiral separation of lactic acid by high performance liquid chromatography is presented. Five chiral stationary phases based on macrocyclic antibiotics were used for enantioseparation and chromatographic parameters, such as retention factors, resolution and selectivity factors, were determined under different column temperatures ranging from 5 to 45 °C. Optical isomers of lactic acid were efficiently separated using chiral stationary phases based on teicoplanin (R_S = 1.9 ) and ristocetin (R_S = 1.7 ) in reversed-phase separation mode at the column temperature of 25 °C.