Extraction of α-tocopherol from serum prior to reversed-phase liquid chromatography

A reversed-phase high-performance liquid chromatographic method for the determination of cw-tocopherol in serum with ultraviolet (UV) absorbance as well as fluorescence detection is described. The fluorescence monitor was considerably more sensitive than the UV monitor. In addition, systematic studies on the influence of different extraction procedures on the recovery of vitamin E were performed. The extraction of vitamin E; from the serum into hexane was markedly affected by the relative volume of ethanol and to a lesser degree by the relative volume of hexane in the mixture. The extracting time also affected the recovery of vitamin E, depending on the amount of ethanol added to the extracting solution. Vitamin E was relatively stable for a considerable length of time when both concentrated and diluted solutions of ethanol and serum were stored in the dark at -20 or 4 degrees C.