ABSTRACT
Recently, Salen et al. (60) reported the separation of plant sterols and stanols as the TMS ethers by GLC/FID using a capillary column (26m×0.32 mm) coated with 0.21µm film of CP-wax-52CB (Chrompack, Bridgewater, NJ) at an isothermal temperature of 210°C and with helium as carrier gas. The plasma dietary sterol concentrations were measured following saponification of plasma or homogenized diet. 5α-Cholestane or coprostanol was added as internal standard prior to extraction of the neutral sterols and stanols with hexane. The solvent was evaporated, and TMS ether derivatives were prepared by the addition of Sil-Prep (Analtech, Deerfield, IL). After standing for 30min, pyridine was evaporated and the residue was dissolved in hexane. The retention times relative to 5α-cholestane for TMS ether derivatives were as follows: cholesterol 1.86, campesterol 2.36, campestanol 2.24, sigmasterol 2.46, sitosterol 2.86, sitostanol 2.72, and avenasterol 3.46. The method was used to demonstrate hyperabsorption and retention of campstanol in a sitosterolemic homozygote (see below).
