Abstract
A simple and highly sensitive high-performance liquid chromatographic method for the determination of free cholestanol and cholesterol in human serum is described. After extraction of the steroids from serum sample (5μl), spiked with 1-eicosanol (internal standard) with n-hexane, these steroids and the internal standard are converted into the corresponding fluorescent derivatives by reaction with 3, 4-dihydro-6, 7-dimethoxy-4-methyl-3-oxo-quinoxaline-2-carbonyl azide. The derivatives are separated on a reversed-phase column (YMC Pack C8) with isocratic elution using acetonitrile-methanol-water (81: 9: 10, v/v/v). The detection limits for; cholestanol and cholesterol were 162 fmol and 144 fmol/5μl in serum, respectively, at a signal-to-noise ratio of 3. The concentrations of free cholestanol and cholesterol in normal sera and a cerebrotendious xanthomatosis serum were compared with those of total cholestanol and cholesterol.
