SIMULTANEOUS DETERMINATION OF ALPHA-TOCOPHEROL AND RETINOL IN PLASMA OR RED-CELLS BY HIGH-PRESSURE LIQUID-CHROMATOGRAPHY

Described is a rapid, microprocedure for the simultaneous determination of α-tocopherol (vitamin E) and retinol A) in plasma, and of α-tocopherol alone in red cells since cells do not contain retinol. A total lipid extract from 0.1 ml plasma or 0.125 ml red cells and containing internal standards of α-tocopheryl acetate and retinyl acetate is injected onto a high pressure liquid chromatograph with a reverse phase column developed with methanol-water. An ultraviolet detector with 280-nm filter is used. The chromatogram is complete in 8 min and the α-tocopherol and retinol are quantitated by the peak height ratio method. Comparison of results with both plasma and red cells gave excellent agreement with conventional methods for these vitamins. The procedure should be particularly useful for clinical studies and nutrition surveys.