Enantiomeric separation of asymmetric triacylglycerol by recycle high-performance liquid chromatography with chiral column

Abstract

In our previous studies, we employed recycle HPLC for the separation of triacylglycerol (TAG)-positional isomers (PIs). In this study, a recycle HPLC system equipped with a polysaccharide-based chiral column was applied to the enantiomeric separation of some asymmetric TAGs having straight-chain C16–C18 acyl residues. As a result, 1,2-dipalmitoyl-3-oleoyl- rac-glycerol ( rac-PPO), 1,2-dioleoyl-3-palmitoyl- rac-glycerol ( rac-OOP), and 1,2-dipalmitoyl-3-linoleoyl- rac-glycerol ( rac-PPL) were resolved into their respective enantiomers. However, neither 1,2-dioleoyl-3-linoleoyl- rac-glycerol ( rac-OOL), consisting of only unsaturated fatty acids, nor 1,2-dipalmitoyl-3-stearoyl- rac-glycerol ( rac-PPS), consisting of only saturated fatty acids, was resolved. These results suggest that the asymmetric TAGs, used in this study, having both a palmitic acid moiety and an oleic acid (or a linoleic acid) moiety at the sn-1 or sn-3 positions are resolved by the chiral column. This new chiral separation method can be used in combination with atmospheric pressure chemical ionization mass spectrometry to determine the sn-OOP/ sn-POO ratio in palm oil. This method is applicable for the chiral separation of asymmetric TAGs in palm oil.