Fast comprehensive two-dimensional gas chromatography method for fatty acid methyl ester separation and quantification using dual ionic liquid columns

•A fast GC × GC method based on coupled IL columns has been developed.•A standard mixture of 37 FAME were resolved to baseline in 16 min.•An IL111/IL59 column set behaved similarly to an IL111/INNOWax column set.•Abundant C18 isomers were successfully separated in safflower and linseed oil.•Several trace FAME were readily detected in safflower oil based on 2D positions.

Safflower oil is a complex mixture of C18 saturated and unsaturated fatty acids amongst other fatty acids, and achieving separation between these similar structure components using one dimensional gas chromatography (GC) may be difficult. This investigation aims to obtain improved separation of fatty acid methyl esters in safflower oil, and their quantification using comprehensive two-dimensional GC (GC × GC). Here, GC × GC separation is accomplished by the coupling of two ionic liquid (IL) column phases: the combination of SLB-IL111 with IL59 column phases was finally selected since it provided excellent separation of a FAME standard mixture, as well as fatty acids in safflower and linseed oil, compared to other tested column sets. Safflower oil FAME were well separated in a short run of 16 min. FAME validation was demonstrated by method reproducibility, linearity over a range up to 500 mg L−1, and limits of detection which ranged from 1.9 mg L−1 to 5.2 mg L−1 at a split ratio of 20:1. Quantification was carried out using two dilution levels of 200-fold for major components and 20-fold for trace components. The fatty acids C15:0 and C17:0 were not reported previously in safflower oil. The SLB-IL111/IL59 column set proved to be an effective and novel configuration for separation and quantification of vegetable and animal oil fatty acids