A new RPLC-ESI-MS method for the determination of eight vitamers of vitamin E

Vitamin E consists of four (α-, β-, γ-, δ-) isoforms of tocopherols (T) and tocotrienols (T3), collectively known as tocols. Current LC methods for tocols suffer from either the poor ability to resolve the β- and γ- isoforms (RPLC), or require the use of nonpolar solvents (NPLC), which complicates subsequent MS/MS detection. Moreover, we show that coupling of UV with MS leads to tocols photodegradation. To solve these problems, we developed a new RPLC-MS/MS method, allowing to resolve not only α- and δ-, but also β- and γ- tocols in hydrophobic matrices. We took advantage of an observation that the peak area ratios are specific for the given isomer and constant. The new method with a linear range between 0.2 and 60 ng·mL^-1 (for α-T) and 1.1-60 ng·mL^-1 (for β-T3 and γ-T3) was validated and employed for quantitative analysis of several oils, including false flax (Camelina sativa) oil stored under different conditions.