Separation of RRR-α-Tocopherol by Chiral Chromatography.

Background: α-Tocopherol can exist as eight possible stereoisomers due to the presence of three chiral carbons. Regulations and industry guidelines necessitate that dietary vitamin E intakes be based on the vitamin E activity of RRR-α-tocopherol. Food products fortified with synthetic all-rac-α-tocopherol or all-rac-α-tocopheryl acetate during manufacturing will require chiral separation of the α-tocopherol stereoisomers for accurate estimation of vitamin E activity.

Objective: The development of an HPLC method utilizing a chiral column for the chromatographic separation of RRR-α-tocopherol from other α-tocopherol stereoisomers.

Method: Normal phase liquid chromatographic separation using a polysaccharide-based chiral column with fluorescence detection of α-tocopherol stereoisomers.

Results: The described chromatographic method achieves baseline resolution of RRR-α-tocopherol from its stereoisomers. Method selectivity, precision, and robustness were evaluated and acceptable performance was achieved.

Conclusions: The chromatographic method was found to be suitable for application where both RRR-α-tocopherol content and total α-tocopherol content are required for routine compliance testing.

Highlights: A robust and precise chomatographic method for the baseline resolution of RRR-α-tocopherol from its stereoisomers was acheived.