Quantitation and occurrence of hydroxy fatty acids in fats and oils

A relatively simple method is detailed for the routine quantitation and isolation of hydroxy fatty acids (HFA) in the glycerides of lipids. The lipid in cyclohexane is transmethylated in a two‐phase, 3.5 min procedure, and the hydroxyl compounds in the methyl ester fraction are derivatized with pyruvic acid chloride 2,6‐dinitrophenyl‐hydrazone in the presence of triethylenediamine. The derivatives are fractionated on alumina, and the HFA fraction is evaluated spectrophotometrically. A large variety of animal, plant and marine lipids contain HFA in concentrations ranging from <10 to >1000 μmoles/g lipid. The derivatives lend themselves admirably to purification techniques. A procedure for regenerating the parent HFA from the derivative is described.