Separation Behavior of Octadecadienoic Acid Isomers and Identification of cis‐ and trans‐Isomers Using Gas Chromatography |
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Authors: | Shigeaki Shibamoto Andrew Gooley Kouhei Yamamoto |
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Affiliation: | 1. +81‐774‐95‐1650;2. , Shimadzu Corporation, Soraku‐gun, Kyoto, Japan;3. SGE Analytical Science, Ringwood, VIC, Australia;4. , Graduate School of Comprehensive Rehabilitation, Osaka Prefecture University, Habikino, Osaka, Japan |
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Abstract: | Using a strongly polar cyanopropyl capillary column we have investigated the gas chromatography (GC) separation behaviors of 24 octadecadienoic acid methyl ester (18:2ME) isomers compared against saturated methyl stearate (18:0ME) and arachidic acid methyl ester (20:0ME), and the dependency on the GC column temperature. The 24 isomers were obtained by performing cis‐to trans‐isomerization of six regioisomers: five of the 18:2ME isomers were prepared by the partial reduction of methyl α‐linolenate and methyl γ‐linolenate C18 trienoic acids with different double bond positions, whereas the sixth isomer, 18:2ME (c5, c9), was obtained from a raw constituent fatty acid methyl ester (FAME) sample extracted from Japanese yew seeds. There are no reference standards commercially available for 18:2ME isomers, and in elucidating the elution order of these isomers this study should help the future identification of cis‐ and trans‐type of 18:2ME. We also report the identification method of cis‐ and trans‐type of FAME using equivalent chain lengths and attempt the identification of cis‐ and trans‐type of 18:2ME isomers from partially hydrogenated canola oil. |
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Keywords: | trans Fatty acid Fatty acid analysis GLC (GC) (gas– liquid chromatography) Mass spectrometry HPLC (high performance liquid chromatography) |
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