One-dimensional and two-dimensional 1H- and 13C-nuclear magnetic resonance (NMR) analysis of vitamin E raw materials or analytical reference standards.
Two-dimensional spectral analysis (COSY, HETCOR) was utilized to make the complete 13C- and 1H-NMR assignments for alpha-, beta-, gamma-, and delta-tocopherol as well as for the acetate and succinate esters of alpha-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 alpha-tocopherol and delta-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 alpha-tocopherol and delta-tocopherol reference materials.
Baker
J K
JK
Department of Medicinal Chemistry, School of Pharmacy, University of Mississippi, University 38677.
Myers
C W
CW
D002247:Carbon Isotopes; D006859:Hydrogen; D009682:Magnetic Resonance Spectroscopy; D012015:Reference Standards; D013237:Stereoisomerism; D014810:Vitamin E / Q000032:analysis*
D002247:Carbon Isotopes; D014810:Vitamin E; D006859:Hydrogen