Liquid chromatography-mass spectrometry determination of free fatty acids in phospholipid-based formulations

A method for the analysis of free fatty acids resulting from the degradatio n of phospholipids was developed using highperformance liquid chromatograph y-mass spectrometry with an electrospray ionization source. Separation of f atty acid molecular species was achieved using an isocratic acidified mixtu re of acetonitrile/water (70:30) on a reversed phased column (C-8). Optimiz ation of the mass spectrometer conditions has allowed the method to separat e and detect the fatty acids mainly as deprotonated molecular species. Sepa ration of all major fatty acids was achieved in less than 6 min. The fatty acids studied provide a linear response over 3 orders of magnitude. Data su pporting the validation of this method are also presented.