*2.7.1 Lipid extraction for analysis by liquid chromatography-mass spectrometry (LC-MS)*

In order to determine TAG in food, initially, is essential to extract the lipids contained on it. Folch [80] and Bligh and Dyer [85] methods are extensively employed for the extraction of milk lipids. The addition of antioxidant, such as BHT is recommended prior to extraction to avoid lipid oxidation [86]. The internal standards for each lipid class are added to the matrix prior to extraction [87].

Preceding the LC–MS analysis, the extraction solvents (chloroform/methanol) must to be removed by evaporation, and the lipids are reconstituted with solvent compatible with the mobile phase of LC. Moreover, a pre-sample of SPE or TLC columns previous to LC–MS analysis may facilitate the lipid species identification due to improved resolution.
