Determination of individual free fatty acids in milk by strong anion-exchange resin and gas chromatography.

A quantitative method for determination of free fatty acids in milk is described. Free fatty acids and some glycerides were extracted from milk in acetonitrile in the presence of sulfuric acid and anhydrous sodium sulfate. The filtered extract was evaporated to dryness. With use of strong anion-exchange resin as heterogeneous basic catalysts, the free fatty acids were methylated directly. The free fatty acids were separated by gas chromatography with a 2000 mm X 2-mm inner diameter glass column packed with 10% SP-2330 on 100/120 mesh Chromosorb W.