Characterization of unsaturated fatty acids with high structural specificity by nuclear magnetic resonance spectroscopy.

Comprehensive characterization of fatty acid (FA) structures has important value, as they are important components of cells and are crucial for cell structure and function. However, in view of the different structural possibilities of unsaturated FAs due to the carbon-carbon double bond (CC) location and its chemical configuration, there are still certain difficulties in characterizing unsaturated FAs with high structural specificity. In this work, we present a method based on nuclear magnetic resonance (NMR) spectroscopy for comprehensive characterization of unsaturated FAs. Combining 1D and 2D-NMR spectroscopy, it could provide diagnostic information specific to CC locations and stereochemistry of unsaturated FAs, facilitating FA isomers identification. Structural characterization of unsaturated FAs at the isomeric level has been validated by examination of multiple sample types through our proposed approach. The capability of the proposed method for relative quantitation of FA isomers utilizing its specific diagnostic peaks was also demonstrated. Unlike conventional approaches requiring both reference standards and extensive sample processing, the current proposed method represents a potential alternative by resolving unsaturated lipid structures at high structural level directly.