A fast, sensitive method for the simultaneous determination of α-tocopherol and α-tocopheryl acetate in mixed micelles

This report improves analytical procedures to investigate the behaviour of the two Vitamin E forms, a-tocopherol (Tol) and alpha-tocopheryl acetate (Tac), in model systems mimicking the intestinal medium. We describe how to prepare mixed micelles as vehicle for Tac and Tol and the HPLC method for their quantification in the micelles. Tac and Tol were extracted using ethanol-hexane-drying procedure, whereas the separation and detection were performed in methanol and by UV method, respectively. Both compounds were eluted in less than 4 min. In the range between 1.7 mu M and 54 mu M of Tac or Tol in the micelles, their recovery were 89% and 81%, respectively, with correlation coefficient over 0.99 and R.S.D. of less than 7.2% in all cases. Limits of detection and quantification for Tac and Tol in mixed micelles ranged between 1 mu M and 2 mu M and between 3 mu M and 5 mu M, respectively. The behaviours of Tac and Tol were quite different during the extraction procedure and both were influenced by the vitamin concentration and the relative volume of organic solvents. (c) 2005 Elsevier B.V. All rights reserved.