title: Analysis of Long-Chain Unsaturated Fatty Acids by Ionic Liquid Gas Chromatography.
abstract: Four ionic liquid (IL) columns, SLB-IL59, SLB-IL60, SLB-IL65, and SLB-IL111, were evaluated for more rapid analysis or improved resolution of long-chain methyl and ethyl esters of omega-3, omega-6, and additional positional isomeric and stereoisomeric blends of fatty acids found in fish oil, flaxseed oil, and potentially more complicated compositions. The three structurally distinct IL columns provided shorter retention times and more symmetric peak shapes for the fatty acid methyl or ethyl esters than a conventional polyethylene glycol column (PEG), resolving cis- and trans-fatty acid isomers that coeluted on the PEG column. The potential for improved resolution of fatty acid esters is important for complex food and supplement applications, where different forms of fatty acid can be incorporated. Vacuum ultraviolet detection contributed to further resolution for intricate mixtures containing cis- and trans-isomers, as exemplified in a fatty acid blend of shorter chain C18:1 esters with longer chain polyunsaturated fatty acid (PUFA) esters.
authors: Department of Chemistry and Biochemistry, University of Texas at Arlington , Arlington, Texas 76019, United States.
authors: Choyce A
authors: CA
authors: Weatherly
authors: Department of Chemistry and Biochemistry, University of Texas at Arlington , Arlington, Texas 76019, United States.
authors: Ying
authors: Y
authors: Zhang
authors: VUV Analytics, Inc. , 715 Discovery Boulevard Suite 502, Cedar Park, Texas 78613, United States.
authors: Jonathan P
authors: JP
authors: Smuts
authors: Department of Chemistry and Biochemistry, University of Texas at Arlington , Arlington, Texas 76019, United States.
authors: Hui
authors: H
authors: Fan
authors: Chengdong
authors: C
authors: Xu
authors: Department of Chemistry and Biochemistry, University of Texas at Arlington , Arlington, Texas 76019, United States.
authors: Kevin A
authors: KA
authors: Schug
authors: Department of Chemistry and Biochemistry, University of Texas at Arlington , Arlington, Texas 76019, United States.
authors: John C
authors: JC
authors: Lang
authors: Department of Chemistry and Biochemistry, University of Texas at Arlington , Arlington, Texas 76019, United States.
authors: Daniel W
authors: DW
authors: Armstrong
mesh_terms: D002849:Chromatography, Gas / Q000379:methods*; D019587:Dietary Supplements / Q000032:analysis; D004952:Esters / Q000032:analysis; D005231:Fatty Acids, Unsaturated / Q000737:chemistry*; D005395:Fish Oils / Q000737:chemistry; D013237:Stereoisomerism
chemical_list: D004952:Esters; D005231:Fatty Acids, Unsaturated; D005395:Fish Oils
keywords: cis and trans isomers; fish oil; flaxseed oil; ionic liquid capillary GC columns; omega-3 fatty acids; omega-6 fatty acids; positional isomers; vacuum ultraviolet detection