Simple method for quantifying α-tocopherol in low-density + very-low-density lipoproteins and in high-density lipoproteins

Abstract

We assessed the distribution of α-tocopherol in serum lipoprotein samples after separating the lipoprotein fractions by either sequential ultracentrifugation or selective precipitation with sodium phosphotungstate-magnesium chloride reagent. α-Tocopherol concentrations were determined by reversed-phase high-performance liquid chromatography. After ultracentrifugation, we found that in men, low- and very-low-density serum lipoproteins (LDL-VLDL) contained 53.6% of α-tocopherol vs 46.4% in high-density lipoproteins (HDL). In women, serum LDL-VLDL contained 45.6% α-tocopherol after ultracentrifugation vs 54.4% in HDL. After selective precipitation, the proportions of α-tocopherol in men were 56.1% in LDL-VLDL vs 43.9% in HDL, and in women, 45.4% in LDL-VLDL vs 54.6% in HDL. After selective precipitation, α-tocopherol recovery from whole lipoprotein fractions was 97% to 100% vs 80% after ultracentrifugation, thus allowing more accurate α-tocopherol quantification than after separation by ultracentrifugation.