Analysis of all-rac-alpha-tocopheryl acetate and retinyl palmitate in medical foods using a zero control reference material (ZRM) as a method development tool

A liquid chromatographic method is described for analysis of all-rac-alpha- tocopheryl acetate and retinyl palmitate in medical food. The vitamins are extracted in isopropyl alcohol and hexane-ethyl acetate without saponificat ion and quantitated by normal-phase chromatography with fluorescence detect ion. All-rac-alpha-tocopheryl acetate and retinyl palmitate are chromatogra phed isocratically with a mobile phase of 0.5% (v/v) and 0.125% (v/v) isopr opyl alcohol in hexane, respectively. Recovery studies performed on a medic al food zero control reference material (ZRM) fortified with the analytes a veraged 99.7% (n = 25) for retinyl palmitate and 101% (n = 25) for all-rac- a-tocopheryl acetate. Coefficients of variation were 0.87-2.63% for retinyl palmitate and 1.42-3.20% for all-rac-alpha-tocopheryl acetate. The method provides a rapid, specific, and easily controlled assay for analysis of vit amin A and vitamin E in medical foods. Use of chlorinated solvents is avoid ed.