Integrated multidimensional and comprehensive 2 D GC analysis of fatty acid methyl esters

Fatty acid methyl ester ( FAME ) profiling in complex fish oil and milk fat samples was studied using integrated comprehensive 2 D GC ( GC × GC ) and multidimensional GC ( MDGC ). Using GC × GC , FAME compounds – cis ‐ and trans ‐isomers, and essential fatty acid isomers – ranging from C 18 to C 22 in fish oil and C 18 in milk fat were clearly displayed in contour plot format according to structural properties and patterns, further identified based on authentic standards. Incompletely resolved regions were subjected to MDGC , with C n (n = 18, 20) zones transferred to a 2 D column. Elution behavior of C18 FAME on various 2 D column phases (ionic liquids IL 111, IL 100, IL 76, and modified PEG ) was evaluated. Individual isolated C n zones demonstrated about four‐fold increased peak capacities. The IL 100 provided superior separation, good peak shape, and utilization of elution space. For milk fat‐derived FAME , the 2 D chromatogram revealed at least three peaks corresponding to C 18:1, more than six peaks for cis / trans ‐ C 18:2 isomers, and two peaks for C 18:3. More than 17 peaks were obtained for the C 20 region of fish oil‐derived FAME s using MDGC , compared with ten peaks using GC × GC . The MDGC strategy is useful for improved FAME isomer separation and confirmation.