Analysis of lecithin in cosmetics by reversed-phase liquid chromatography/electrospray tandem mass spectrometry

Abstract

A rapid, sensitive and selective method by reversed-phase liquid chromatography (LC) with electrospray ionization (ESI) mass spectrometry (MS) was employed for the determination of lecithin in a cosmetic raw material for quality control of the product formulation. The mixture of the phosphatidylcholine, phosphatidyl-ethanolamine, and phosphatidylinositol in lecithin was separated using aqueous methanol–acetonitrile solvent with a reversed-phase LC column, and detected as forms of pseudomolecular ions. Using this LC/ESI-MS technique, simultaneous separation and detection of phospholipid classes and molecular species within each class were achieved for the first time. Additionally informative fragmentation patterns were obtained by employing LC/ESI-MS/MS in both positive and negative ionization modes to identify these fatty acid chains and polar head groups in each molecular species of the phospholipids. © 1998 John Wiley & Sons, Ltd.