Determination of α-tocopherol and α-tocopheryl acetate in diets of experimental animals

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

“…The extraction procedures of Vitamin E from plasma by mean of ethanol and hexane, including a drying step, have been described in several studies [3,4,8,10]. The general lines of our extraction procedure are similar to those decribed by Hoehler et al [8] for serum, however specific modifications needed to be applied as micelles were concerned.…”

“…The general lines of our extraction procedure are similar to those decribed by Hoehler et al [8] for serum, however specific modifications needed to be applied as micelles were concerned. The importance of some steps of the extraction procedure are discussed in the results and discussion section.…”

“…In some protocols, an aliquot of the organic phase is then directly injected into the HPLC system [1][2][3], whereas in other more frequent procedures the organic phase is dried before the vitamin is redissolved in a less apolar organic solvent, which is then injected into the chromatograph [4][5][6][7][8][9]. For separation, the most common mobile phase is methanol or methanol-based solvents, generally under isocratic conditions [1][2][3][5][6][7][8][9]. Detection is performed using either fluorimetric [10,11], electrochemical [12,13] or spectrophotometric [1][2][3][4]14] means.…”

“…Detection is performed using either fluorimetric [10,11], electrochemical [12,13] or spectrophotometric [1][2][3][4]14] means. Coupled UV and fluorescence detection is also used if more than one compound has to be determined [6][7][8]15,16]. It is interesting to note that all these detection methods allow for determination of Vitamin E in almost all in vitro and in vivo situations, though the fluorescence detection is the most sensitive.…”

“…The published HPLC methods describe the simultaneous determination of Tac and Tol, for example, in human stools [3], diets for animals [8] and fish feed [15]. These methods have different extraction procedures and detection means, but commonly used methanol as mobile phase.…”