EFFECT OF TEMPERATURE ON CHIRAL AND ACHIRAL SEPARATIONS OF DIACYLGLYCEROL DERIVATIVES BY HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY ON A CHIRAL STATIONARY PHASE

Enantiomer separation of 1,2-diacyl-rac-glycerols (1,2-rac-DGs) as their 3,5-dinitrophenylurethane derivatives by high-performance liquid chromatography was carried out on a Sumichiral OA-4100 column. The separation of 1,2-DG enantiomers was improved by lowering the temperature. Linear relationships were found between the logarithm of the separation factor and the reciprocal of absolute temperature. Using thermodynamic concepts, detailed considerations are presented for the enantiomer separation and separation of molecular species differing in carbon number or olefinic bond number. Separation by carbon number is controlled by entropy differences, whereas separation by double bond number is based on enthalpy contributions.