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 degradation of phospholipids was developed using highperformance liquid chromatography-mass spectrometry with an electrospray ionization source. Separation of fatty acid molecular species was achieved using an isocratic acidified mixture of acetonitrile/water (70:30) on a reversed phased column (C-8). Optimization of the mass spectrometer conditions has allowed the method to separate and detect the fatty acids mainly as deprotonated molecular species. Separation 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 supporting the validation of this method are also presented.