Analysis of triacylglycerols in refined edible oils by isocratic HPLC-ESI-MS

A simple, fast and reproducible reversed-phase high performance liquid chromatography (HPLC) method coupled to electrospray ionization mass spectrometry (ESI-MS) for the analysis of triacylglycerols (TAGs) species in the commercial edible oils has been developed. The TAGs species were separated using isocratic 18% isopropanol in methanol and a Phenomenex C18 column. The ESI-MS conditions were optimized using flow injection analysis of standard TAG. Fifteen, fourteen, and sixteen TAGs were separated and identified in corn oil, rapeseed oil, and sunflower oil, respectively. The presence of intense protonated molecular (M + H+), ammonium (M + NH4+), and sodium (M + Na+) adducts ions and their respective diacylglycerols ions in the ESI-MS spectra showed correct identification of TAGs. Some minor potassium adducts (M + K+) were also found. In addition, the identity of the fatty acid, position of each fatty acid, and the location of the double bond in the fatty acid moiety were explained. It was found that this isocratic method is useful for fast screening and identification of triacylglycerols in lipids.