Development and validation of HPLC method for simultaneous quantification of alpha-tocopherol (free or encapsulated) and cholesterol in semen cryopreservation media

The HPLC method was developed and validated for assaying alpha-tocopherol and cholesterol in cryopreservation media. Chromatographic separation was performed on an isocratic system, using a C-18 column. The mobile phase was composed of a mixture of methanol:acetonitrile:water 68:28:4 (v/v/v), using a flow rate of 1.5 mL/min and 20 μL injection volume, at a wavelength of 208 nm. The method was validated according to International Conference on Harmonization guidelines. The method proved to be specific, accurate, precise, and linear with correlation coefficients greater than 0.996 over a wide concentration range of both analytes. Vitamin E and cholesterol presented limits of detection of 0.002 mg/mL, 0.026 mg/mL and limits of quantitation of 0.006 mg/mL, 0.086 mg/mL, respectively. This method is simple and rapid, shows high precision and accuracy, and offers the advantage of simultaneous assaying of vitamin E and cholesterol (alone, in cyclodextrins complexes or in liposome loaded) on semen cryopreservation media.