EXTRACTION OF ALPHA-TOCOPHEROL FROM SERUM PRIOR TO REVERSED-PHASE LIQUID-CHROMATOGRAPHY

A reversed-phase high-performance liquid chromatographic method for th e determination of cw-tocopherol in serum with ultraviolet (UV) absorb ance as well as fluorescence detection is described. The fluorescence monitor was considerably more sensitive than the UV monitor. In additi on, systematic studies on the influence of different extraction proced ures on the recovery of vitamin E were performed. The extraction of vi tamin E; from the serum into hexane was markedly affected by the relat ive 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 extract ing solution. Vitamin E was relatively stable for a considerable lengt h of time when both concentrated and diluted solutions of ethanol and serum were stored in the dark at -20 or 4 degrees C.