Determination of cis- and trans-18:1 fatty acid isomers in hydrogenated vegetable oils by high-resolution carbon nuclear magnetic resonance

Carbon nuclear magnetic resonance (C-13 NMR) methods for determining the composition of cis-/trans- and positional isomers in hydrogenated vegetable oils were developed to reduce analytical time. By selecting appropriate olefinic carbon peaks and by measuring individual peak areas subsequent to the identification of isomeric peaks on the NMR spectrum, compositional results of the isomers coincided well with those obtained by conventional gas chromatography (CC). Therefore, it is highly beneficial to choose the C-13 NMR method when analysis time is limited. Though the proposed C-13 NMR method is promising, further development is needed. For the time being, combination with the traditional CC method is still encouraged for precise compositional analysis of cis-/trans- and positional isomers.