DETERMINATION OF VITAMINS A, E, AND K AND UBIQUINONES IN PLASMA BY VERY HIGH SPEED LIQUID CHROMATOGRAPHY

抄録

A quantitative method for analyzing vitamins A, E and K and ubiquinones in plasma, based on recently developed very high speed liquid chromatography, is described. Vitamins A, E, and K and ubiquinones are extracted from 20 - 50 μl of plasma with 5 ml of hexane after addition of 1 ml of water and 2 ml of ethanol containing each internal standard. Hexane extracts ( 4 ml ) are evaporated under a nitrogen stream at 40°C. The residue is dissolved in 100 μl of isopropanol or hexane. The solution is subjected to the very high speed liquid chromatography. Total time required for sample preparation and analysis is some 10 min. The actual chromatographic separation is completed in about 5 min. The detection limits for vitamin A ( retinol ), vitamin E (α-tocopherol ), vitamin K₁ and ubiquinone-10 obtained with a UV detector are 0.056, 0.28, 0.28 and 0.49 ng, respectively. This method offers significant advantages in terms of sensitivity and speed of sample treatment compared to conventional methods.