Vitamin E in foods: Determination of tocols and tocotrienols

Abstract

Abstract A method is described for the analysis of foods for the forms of vitamin E. Detailed procedures are given for extraction, saponification and partial purification by thin layer chromatography. The individual tocopherols (both tocols and tocotrienols) are identified and estimated as their trimethylsilyl ethers by gas liquid chromatography on SE‐30 or Apiezon L at 235 C. Retention ratios are also given for separations on OV‐17. Response factors relative to didecyl pimelate as an internal standard and overall recoveries were determined for α‐tocopherol, β‐tocopherol, γ‐tocopherol, δ‐tocopherol, β‐tocotrienol and α‐tocotrienol. Sample sizes depended on tocopherol content and were usually chosen to contain 3–50 µg of the individual tocopherols. Data for a number of seeds and oils are given. The greatest variety of forms was found in barley, which contains all the forms listed above, plus γ‐tocotrienol.