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13 C nuclear magnetic resonance spectral confirmation of Δ6‐and Δ7‐ trans ‐18:1 fatty acid methyl ester positional isomers
Author(s) -
Mazzola E. P.,
McMahon J. B.,
McDonald R. E.,
Yurawecz M. P.,
Sehat N.,
Mossoba M. M.
Publication year - 1997
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/s11746-997-0066-4
Subject(s) - chemistry , structural isomer , derivatization , cis–trans isomerism , mass spectrometry , double bond , fatty acid , unsaturated fatty acid , gas chromatography , fatty acid methyl ester , chromatography , stereochemistry , organic chemistry , biodiesel , catalysis
Trans octadecenoic acid methyl ester isomers were obtained from a partially hydrognated soybean oil and isolated by silver‐ion high‐performance liquid chromatography. Recently, the double‐bond positions for nine individual trans octadecenoic acid positional isomers (Δ8 through Δ16) were confirmed by gas chromatography‐electron ionization mass spectrometry after derivatization to 2‐alkenyl‐4,4‐dimethyloxazoline. In this communication, the presence of two additional trans ‐18:1 fatty acid methyl ester positional isomers (Δ6 and Δ7) in the same mixture is confirmed by 13 C nuclear magnetic resonance spectroscopy. The identity of the Δ5‐ trans ‐18:1 fatty acid methyl ester positional isomer is inferred.