Partition of Lipid Classes in Extra Virgin Olive Oil via Classic Liquid Chromatography and Subsequent Characterization Employing GC-FID and ESI-MS

Olive oil is daily consumed due to its exceptional properties, such as pleasant organoleptic characteristics, oxidative stability, and chemical composition. Moreover, the edible oil has a high content of several compounds, for example, hydrocarbons, tocopherols, aliphatic alcohols, volatile phenolic compounds, pigments, lipids, among others. In order to properly separate, identify, and quantify all lipid species present in olive oil, adequate analytical methods are indispensable. Therefore, this study aimed to employ classic liquid chromatography to separate, identify and quantify the lipid classes in olive oil employing classic liquid chromatography (CLC), gas chromatography with flame ionization detector (GC-FID), and direct infusion by electrospray ionization mass spectrometry (ESI-MS). The results indicated a higher percentage of monounsaturated fatty acids (MUFA) in the non-polar lipid fraction than in the polar fraction, which in turn displayed higher content of saturated fatty acids (SFA) due to its greater affinity towards the stationary phase, while the unsaturated fatty acids (UFA) displayed stronger interactions with the mobile phase. These results concur with those obtained by ESI-MS, which proved possible the partition of polar and non-polar lipid fractions of olive oil by CLC, and that the major triacylglycerols (TAG) of olive oil were identified in the neutral lipid fraction.

Automated summary

The study utilized classic liquid chromatography, gas chromatography with flame ionization detector, and direct infusion by electrospray ionization mass spectrometry to separate, identify, and quantify lipid classes in olive oil. Results revealed higher percentage of monounsaturated fatty acids in the non-polar lipid fraction than in the polar fraction, indicating different affinities of fatty acids towards stationary and mobile phases. The major triacylglycerols of olive oil were identified in the neutral lipid fraction, supporting the partition of polar and non-polar lipid fractions by classic liquid chromatography.