Quantification of tocomonoenols and other tocochromanols in edible plant oils by gas chromatography coupled with mass spectrometry

Tocomonoenols (T1) are considered rare and low abundant tocochromanol compounds that have been found only in a few matrices. We developed a sample preparation strategy for GC/MS-SIM analysis capable of determining T1 and even tocodienols (T2) alongside tocopherols (T) and tocotrienols (T3) after silylation. The slight difference in polarity of individual tocochromanols required the application of two sample preparation methods. Once established, 29 edible plant oils from 22 different plant species were investigated. The recent isolation of 11´-α-T1 and 11´-γ-T1 enabled an exact quantification of these T1 homologues. Specifically, T1 were determined in 17 of 22 oil types. Both the variety and the amounts of T1 were higher compared to T3. Ratios between T and T1 produced evidence that T1 may be formed by hydrogenation of T3 into T as intermediate products. Our results indicate that more attention should be put on the analysis and biochemical investigation of T1 and T2. • A GC/MS method was developed to analyze tocochromanols thoroughly in edible oils. • 10 tocochromanols (vitamin E compounds) were determined in 22 types of plant oils. • α-tocomonoenol (α-T1) and γ-tocomonoenol (γ-T1) were quantified with standards. • α-T1 and/or γ-T1 were detected and quantified in 17 of the 22 types of plant oils. • Tocomonoenols were more frequently detected and more abundant than tocotrienols.