Analysis of Tocopherols and Tocotrienols in Pharmaceuticals and Foods: A Critical Review

Vitamin E (VE) is one category of important fat-soluble vitamins for human normal growth, which consists of eight isomers known as alpha-, beta-, gamma- and delta-tocopherol and alpha-, beta-, gamma- and delta-tocotrienol. Each of the isomers has unique and potent physiological functions, thus it is important to analyze VE isomers respectively. This review briefly introduces physiological functions of tocopherols and tocotrienols, and presents the progress of sample pretreatment and analysis of these compounds in pharmaceuticals and foods in the last decade, then makes a comparison in the aspects of sensitivity, selectivity and simplicity of the various analytical methods. Due to their high efficiency, speedness, inexpensiveness and environmental friendliness, nano-LC and capillary electrophoresis including non-aqueous capillary electrophoresis (NACE), capillary electrochromatography (CEC) and microemulsion electrokinetic chromatography (MEEKC) have been applied in the analysis of VE family, which will also be discussed in this review.