FAME Analysis with Ionic Liquid Capillary Columns
Leonard M. Sidisky, Greg A. Baney, James L. Desorcie, Gustavo Serrano, 
Supelco, Division of Sigma Aldrich, Bellefonte, PA, USA

Analyses of fatty acid methyl esters (FAMEs) are continuing to gain importance as more research is focusing on their biomedical impacts. This includes the analysis of saturated 
and polyunsaturated FAMEs along with the positional geometric (cis and trans) FAME isomers. Traditionally, FAME analyses have been performed using silicone polymer or polyethylene glycol based stationary phases that yield typical elution patterns. Analysts performing the task of analyzing the fatty acid composition of food have a wide variety of capillary column selectivity’s available for resolving the fatty acids as FAMEs depending upon the information they require from their analyses. Nonpolar methylsilicone columns provide a boiling point separation of the FAME isomers with limited resolution of polyunsaturated isomers. Polar polyethylene glycol (PEG) columns resolve the isomers by degree of unsaturation with minimal overlap of the carbon chain lengths. The highly polar cyanosilicone columns will resolve cis and trans isomers along with possibly providing positional geometric isomer separations depending upon the column type. New classes of stationary phases based on Ionic Liquid technology have been developed and have demonstrated to provide unique elution patterns for FAME isomers compared to the traditional silicone or polyethylene glycol based stationary phases. The two new phases are SLB-IL60 with a PEG like selectivity and the SLB-IL111 with highly polar selectivity. We will compare and contrast the selectivity of the ionic liquid phases with polymeric based phases for various FAME samples. Window diagramming of combinations of various ionic liquid phases will also be examined.