title: Separation of the fatty acids in menhaden oil as methyl esters with a highly polar ionic liquid gas chromatographic column and identification by time of flight mass spectrometry.
abstract: The fatty acids contained in marine oils or products are traditionally analyzed by gas chromatography using capillary columns coated with polyethylene glycol phases. Recent reports indicate that 100 % cyanopropyl siloxane phases should also be used when the analyzed samples contain trans fatty acids. We investigated the separation of the fatty acid methyl esters prepared from menhaden oil using the more polar SLB-IL111 (200 m × 0.25 mm) ionic liquid capillary column and the chromatographic conditions previously optimized for the separation of the complex mixture of fatty acid methyl esters prepared from milk fat. Identifications of fatty acids were achieved by applying Ag(+)-HPLC fractionation and GC-TOF/MS analysis in CI(+) mode with isobutane as the ionization reagent. Calculation of equivalent chain lengths confirmed the assignment of double bond positions. This methodology allowed the identification of 125 fatty acids in menhaden oil, including isoprenoid and furanoid fatty acids, and the novel 7-methyl-6-hexadecenoic and 7-methyl-6-octadecenoic fatty acids. The chromatographic conditions applied in this study showed the potential of separating in a single 90-min analysis, among others, the short chain and trans fatty acids contained in dairy products, and the polyunsaturated fatty acids contained in marine products.
authors.affiliation: Office of Regulatory Science, Center for Food Safety and Applied Nutrition, HFS-717, US Food and Drug Administration, 5100 Paint Branch Pkwy, College Park, MD, 20740, USA, alireza.fardinkia@fda.hhs.gov.
authors.forename: Ali Reza
authors.initials: AR
authors.lastname: Fardin-Kia
authors.forename: Pierluigi
authors.initials: P
authors.lastname: Delmonte
authors.forename: John K G
authors.initials: JK
authors.lastname: Kramer
authors.forename: Gerhard
authors.initials: G
authors.lastname: Jahreis
authors.forename: Katrin
authors.initials: K
authors.lastname: Kuhnt
authors.forename: Viviana
authors.initials: V
authors.lastname: Santercole
authors.forename: Jeanne I
authors.initials: JI
authors.lastname: Rader
mesh_terms: D002849:Chromatography, Gas / Q000295:instrumentation / Q000379:methods*; D004952:Esters / Q000032:analysis / Q000737:chemistry; D005227:Fatty Acids / Q000032:analysis* / Q000737:chemistry*; D005395:Fish Oils / Q000032:analysis / Q000737:chemistry*; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods; D013058:Mass Spectrometry / Q000379:methods*
chemical_list: D004952:Esters; D005227:Fatty Acids; D005395:Fish Oils; C033266:Menhaden oil
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