Abstract
Two-dimensional spectral analysis (COSY, HETCOR) was utilized to make the complete 13C- and 1H-NMR assignments for α-, β-, -γ-, and δ-tocopherol as well as for the acetate and succinate esters of α-tocopherol. 13C-NMR was found to be especially useful in distinguishing between the various tocopherols and distinguishing between the d-isomer and the d,l-racemic mixture. HETCOR spectra were also found to be useful for the qualitative identification of mixtures of the tocopherols and sesame oil. Using a procedure designed to minimize errors arising from spin relaxation and nuclear Overhauser effects, 13C-NMR peak integrals were used to quantitate α-tocopherol and δ-tocopherol in the presence of sesame oil using benzoic acid as the standard for calibration of the quantitation. The NMR results were compared to a capillary column gas chromatographic analysis of the individual α-tocopherol and δ-tocopherol reference materials.
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Chris W. Myers: Recipient of the “Analysis and Pharmaceutical Quality Section Undergraduate Award in Pharmaceutical Analysis” from the APQ Section of the American Association of Pharmaceutical Scientists.
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Baker, J.K., Myers, C.W. One-Dimensional and Two-Dimensional 1H- and 13C-Nuclear Magnetic Resonance (NMR) Analysis of Vitamin E Raw Materials or Analytical Reference Standards. Pharm Res 8, 763–770 (1991). https://doi.org/10.1023/A:1015810303089
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DOI: https://doi.org/10.1023/A:1015810303089