title: Gas chromatographic separation of docosenoic acid positional isomers on an SLB-IL100 ionic liquid column.
abstract: Gas chromatography (GC) of docosenoic acid (22:1) has been performed for the separation of positional isomers on the novel SLB-IL100 column with a highly polar ionic liquid stationary phase. A test mixture of 22:1 methyl esters prepared from total lipids of flounder was subjected to GC on a 60 m×0.32 mm i.d. column at an isothermal temperature of 150°C-180°C. On this column, all five positional isomers separated in the elution order of 22:1n-15, 22:1n-13, 22:1n-11, 22:1n-9, and 22:1n-7. The positional isomers, 22:1n-15, 22:1n-13, and 22:1n-11, unresolvable on conventional polar polymer phase columns, were almost completely separated from each other within 24 min at 170°C. The equivalent chain length values of 22:1n-11 to 22:1n-7 were parallel to those on polyethylene glycol and cyanopropyl polysiloxane columns, whereas 22:1n-15 and 22:1n-13 were relatively lower and closer to saturated 22:0 acid. Similar findings were also obtained for co-injected 20:1n-15 to 20:1n-11 isomers. Analysis of fish 22:1 revealed that 22:1n-13 is not always a minor isomer, as previously reported for several samples. The results of this study confirm the view that SLB-IL100 is a powerful tool for GC analysis of monounsaturated fatty acids.
authors.affiliation: Division of Marine Life Sciences, Faculty of Fisheries Science, Hokkaido University, 3-1-1 Minato-cho, Hakodate, Hokkaido 041-8611, Japan.
authors.forename: Kana
authors.initials: K
authors.lastname: Shimizu
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Ando
mesh_terms: D000818:Animals; D004220:Disulfides / Q000737:chemistry; D004883:Erucic Acids / Q000737:chemistry* / Q000302:isolation & purification*; D004952:Esters / Q000302:isolation & purification; D005395:Fish Oils / Q000737:chemistry; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D052578:Ionic Liquids / Q000737:chemistry*; D007536:Isomerism; D011108:Polymers / Q000737:chemistry; D015203:Reproducibility of Results
chemical_list: D004220:Disulfides; D004883:Erucic Acids; D004952:Esters; D005395:Fish Oils; D052578:Ionic Liquids; D011108:Polymers; C021181:dimethyl disulfide