LIQUID-CHROMATOGRAPHIC METHOD FOR ANALYSIS OF ALL-RAC-ALPHA-TOCOPHERYL ACETATE AND RETINYL PALMITATE IN SOY-BASED INFANT FORMULA USING A ZERO-CONTROL REFERENCE MATERIAL (ZRM) AS A METHOD DEVELOPMENT TOOL

A liquid chromatographic method is described for analysis of all-rac-a lpha-tocopheryl acetate, tocopherols, and retinyl palmitate in soy-bas ed infant formula. The vitamins are extracted in isopropyl alcohol and hexane-ethyl acetate without saponification and quantitated by normal -phase chromatography with fluorescence detection. All-rac-alpha-tocop heryl acetate and retinyl palmitate are quantitated isocratically with mobile phases of 0.5% (v/v) and 0.125% (v/v) isopropyl alcohol in hex ane, respectively. Recoveries from zero control reference material soy -based formula averaged 97.2% (n = 25) for retinyl palmitate and 100% (n = 25) for all-rac-alpha-tocopheryl acetate, Coefficients of variati on ranged from 1.21 to 2.86% for retinyl palmitate and from 1.49 to 5. 16% for all-rac-alpha-tocopheryl acetate. The method provides a rapid, specific, and easily controlled assay for analysis of vitamin A and v itamin E in fortified infant formula. Additionally, the method elimina tes use of chlorinated solvents.