Thirteen molecular species of tetraacylglycerols in the seed oil of Physaria fendleri were recently identified. We report here the quantification of the molecular species of these tetraacylglycerols using HPLC with evaporative light scattering detector and the MS of the HPLC fractions. The ion signal intensities of MS1 from the molecular species of acylglycerols with different m/z in HPLC fractions were used to estimate the ratios of the molecular species. The ratios of the molecular species of acylglycerols with the same mass were estimated by the total ion signal intensities of the fragment ions of MS2, [M + Li ? FA]+ and [M + Li ? FA-FA]+. The content of tetraacylglycerols was about 1%. The highest contents of the molecular species of tetraacylglycerols were from those containing one normal FA (non-hydroxylated fatty acid) and they were LsLsLsO (0.25%), LsLsLsL (0.24%), LsLsLsLn (0.21%) and LsLs-OH20:2-O (0.19%). The contents of the tetraacylglycerols containing two normal FA were lower than those containing one normal FA. Among them the highest were LsLsOL (0.10%), LsLsOO (0.06%) and LsLsOLn (0.06%).
Author(s): Jiann-Tsyh Lin, and Grace Q. Chen