All of the analyses were performed at ambient temperature. The mobile phase was a mixture of acetonitrile–deionized water (98:2, vol/vol), and the absorption wavelength in the UV detector was 292 nm. Samples with 3 μL volume and a flow ratio of 1 mL·min-1 were used for analysis. The amount of each compound, namely a-tocopherol, γ-tocopherol, and δ-tocopherol, was calculated from the results obtained for each standard.