High-performance liquid chromatographic and spectrofluorometric determination of α-tocopherol in a natural plant: Ferula hermonis (Zalooh root)

A high-performance liquid chromatographic (HPLC) method for the determination of α-tocopherol in a natural plant (Ferula hermonis–Zalooh roots) is reported. The method includes saponification of samples and extraction of α-tocopherol with a mixture of acetonitrile and methanol (1:1 v/v). However, the presence of α-tocopherol in Zalooh is confirmed with HPLC-UV and fluorescence detection. A spectrofluorometric and the internal addition standard methods are also used to quantify the α-tocopherol in the plant. An internal standard method is based on a known concentration of α-tocopherol that is added in every sample that is analyzed. Alpha-tocopherol levels as determined in samples by HPLC with UV and fluorescence detection ( ≈ 5 ± 0.5 mg / g ) did not differ significantly from the levels determined by Shimadzu spectrofluorometer ( 4.9 ± 0.5 mg / g ). However, the amount of tocopherol determined by both techniques in Zalooh roots was relatively very high. Standards were checked for linearity giving correlation coefficients that were higher than 0.99 in the concentration range of 1 and 6 μmol L−1.