Theoretical Aspects of Triacylglycerin Positional Isomer Separation on Reverse Phase High Performance Liquid...

The purpose of the present study is to bear our hypothesis and to make a profound discussion on the theoretical aspects of triacylglycerin (TG) positional isomer separation on reverse phase high performance liquid chromatography (HPLC). Authentic triacid TG positional isomers and authentic diacid TG positional isomers were injected to a monomeric and polymeric HPLC. Relationship between TG molecular structure and those elution profiles were carefully analyzed. In polymeric column, thickness of the ODS chain is high compared to monomeric column. And for this reason, clearances between the ODS stationary phase chains are considered to be very limited compared to those of monomeric column, thus limiting the TG molecule transformations and rotations to only a "longest stem direction" which gives the smallest resistance in passing through the ODS chains. The longest stem direction of the TG molecule was considered to be the crucial factor for the interaction between the stationary phase. And under this condition, interference occurring between the fatty acid moieties must be the main contributing factor for positional isomer separation in polymeric column. These aspects were considered to explain why they are not consistent with the addition theorem of A.J.P. Martin in partition chromatography.