Premium
Gas‐liquid chromatography‐mass spectrometry of the 4,4‐dimethyloxazoline derivatives of Δ5‐unsaturated polymethylene‐interrupted fatty acids from conifer seed oils
Author(s) -
Berdeaux Olivier,
Wolff Robert L.
Publication year - 1996
Publication title -
journal of the american oil chemists' society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.512
H-Index - 117
eISSN - 1558-9331
pISSN - 0003-021X
DOI - 10.1007/bf02525463
Subject(s) - pinaceae , chemistry , cupressaceae , cis–trans isomerism , gas chromatography , polyunsaturated fatty acid , mass spectrometry , double bond , fatty acid , mass spectrum , stereochemistry , chromatography , organic chemistry , botany , pinus <genus> , biology , pollen
Abstract The fatty acids from the seed oils of three Conifer species (one Pinaceae, Pinus pinaster , and two Cupressaceae, Chamaecyparis lawsoniana and Biota orientalis ) have been analyzed as their 4,4‐dimethyloxazoline (DMOX) derivatives by gas‐liquid chromatography coupled with mass spectrometry. The structures of six Δ5‐unsaturated polymethylene‐interrupted fatty acids (Δ5‐UPIFA) were established, confirming previous studies in which they were identified by their equivalent chainlengths (ECL) and by comparison with related authentic standards. These acids were: cis ‐5, cis ‐9 18∶2, cis ‐5, cis ‐9, cis ‐12 18∶3 ( P. pinaster ), cis ‐5, cis ‐9, cis ‐12, cis ‐15 18∶4 ( C.lawsoniana ), cis ‐5, cis ‐11 20∶2, cis ‐5, cis ‐11, cis ‐14 20∶3 (all species), cis ‐5, cis ‐11, cis ‐14, cis ‐17 20∶4 ( B. orientalis ) acids. In addition, cis ‐9 18∶1, cis ‐9, cis ‐12 18∶2 (all species) and cis ‐9, cis ‐12, cis ‐15 18∶3 (Cupressaceae) acids, together with their elongation products [ cis ‐11 20∶1, cis ‐11, cis ‐14 20∶2 (all species) and cis ‐11, cis ‐14, cis ‐17 20∶3 ( B. orientalis ) acids] were also identified. In the mass spectra, DMOX derivatives of all Δ5‐UPIFA showed an intense peak at m/z 153, which is a diagnostic ion of fatty acid derivatives with a Δ5‐ethylenic bond. Other double bonds were localized by ion pairs that differed by 12 atomic mass units. The present study fully justifies the use of ECL to identify Δ5‐UPIFA in Conifer seed oils, in which they are ordinary components.