title: Evaluation of the retention pattern on ionic liquid columns for gas chromatographic analyses of fatty acid methyl esters.
abstract: Fatty acid methyl esters from marine sources were analyzed by gas chromatography-mass spectrometry on three ionic liquid columns, SLB-IL61, SLB-IL82 and SLB-IL100 (Supelco). Retention indices (equivalent chain lengths) are reported for more than 100 compounds and the overlap patterns are evaluated from these data. The influence of chromatographic conditions on the retention indices of unsaturated fatty acid methyl esters is also evaluated. Compared to typical alternative phases the retention patterns on all three columns are highly dependent on the conditions. The SLB-IL61 phase had overlaps between nutritionally important fatty acids that could not be resolved by changing the chromatographic conditions. This column is therefore regarded as unsuitable for clinical and nutritional studies of the fatty acid composition, but similar overlaps may be avoided on IL82 and IL100. On all three columns double bonds close to the carboxyl group in the analytes contribute with limited retention, which makes it challenging to predict the retention of polyunsaturated fatty acid methyl esters.
authors.affiliation: Department of Chemistry, University of Bergen, P.O. Box 7803, NO-5020 Bergen, Norway.
authors.forename: Chen-Chen
authors.initials: CC
authors.lastname: Lin
authors.affiliation: Department of Chemistry, University of Bergen, P.O. Box 7803, NO-5020 Bergen, Norway.
authors.forename: Ziar
authors.initials: Z
authors.lastname: Wasta
authors.affiliation: Department of Chemistry, University of Bergen, P.O. Box 7803, NO-5020 Bergen, Norway; Nofima BioLab, Kjerreidviken 16, NO-5141 Fyllingsdalen, Norway. Electronic address: Svein.Mjos@kj.uib.no.
authors.forename: Svein A
authors.initials: SA
authors.lastname: Mjøs
mesh_terms: D002623:Chemistry Techniques, Analytical / Q000379:methods*; D002849:Chromatography, Gas; D004952:Esters / Q000032:analysis*; D005227:Fatty Acids / Q000032:analysis*; D008401:Gas Chromatography-Mass Spectrometry; D052578:Ionic Liquids / Q000737:chemistry*
chemical_list: D004952:Esters; D005227:Fatty Acids; D052578:Ionic Liquids
keywords: Equivalent chain lengths (ECL); Fatty acid methyl esters; Gas chromatography–mass spectrometry; Ionic liquid columns