Identification of α-Tocopherol and Its Oxidation Products by Ultra-Performance Liquid Chromatography Coupled. with Quadrupole Time-of-Flight Mass Spectrometry

This study aimed to determine alpha-tocopherol (alpha-T) and its thermal oxidation products simultaneously. A novel method based on an ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS) was developed. This approach was achieved by means of a BEH C18 analytical column under gradient elution conditions with eluents of acetonitrile/isopropanol (1:9, v/v) and acetonitrile/water (4:6,v/v). Compounds were elucidated through exact molecular mass and fragmentation ions obtained from the Q-TOF-MS detector. Two oxidation products, alpha-tocopheryl quinone and 5-formyl-gamma-tocopherol, were identified, and one new compound was determined. This approach offered a simple, precise, and reliable method to determine oxidation products of alpha-T, which may give a way to understand the mechanism of the thermal oxidative process of alpha-T.