Simultaneous HPLC analysis of alpha-tocopherol and cholesterol in fresh pig meat

A method has been developed for simultaneously determining alpha-tocopherol and cholesterol in fresh pig meat by HPLC. It allows a reduction in the number of analyses and brings savings in time and materials. The unsaponifiable fraction is extracted following the modified method of Liu et al. (Liu, Q.; Scheller, K. K.; Schaefer, D. M. Technical note: A simplified procedure for vitamin E determination in beef muscle. J. Anim. Sci. 1996, 74, 2406-2410). The modifications introduced are the use of nitrogen atmosphere during the extraction, the addition of an antioxidant in the organic extraction phase, and the use of alpha-tocopherol itself as an internal standard. There is then a chromatographic analysis which allows the separation of the two compounds in question. To identify and quantify, two different detectors are used in series: the first is a fluorescence detector (alpha-tocopherol), and the second is a light-scattering detector (cholesterol). The technique shows sufficient sensitivity to determine the normal levels of alpha-tocopherol and cholesterol in meat, with recovery percentages of 78% and 97%, respectively. The average amount of alpha-tocopherol and cholesterol in samples from pig Longissimus dorsi muscle analyzed using this method is 1.8 and 620 mg/kg of fresh meat, respectively.