Nucleosil 100 5

Tocopherols were measured directly by high-performance liquid chromatopgraphy (HPLC) of hexane solution of oil (400 µg sample size). The analyses were performed by Agilent 1100 apparatus equipped with Nucleosil 100-5 (250 mm × 4.6 mm, 5 µm) column, connected with a pre-column EC 4/3 Nucleosil 100-5 (Macherey-Nagel) and DAD detector at 292 and 298 nm for α- and γ-isomers, respectively. The mobile phase was a mixture of hexane and tetrahydrofuran (96:4 v/v) at flow rate of 1 mL/min [41 ]. Quantitation was performed using a calibration curve of tocopherol in a range from 0.025 to 0.05 mg/mL, and the results were presented as (mg tocopherol/kg oil).

Reaction samples were analyzed for the quantification of the remaining 2,4-DCP using a SHIMADZU LC-20AD HPLC equipped with a SIL-20A autosampler. A C-18 reverse-phase NUCLEOSIL® 100-5 (Macherey-Nagel, Düren, Germany) served as the stationary phase and 40% aqueous acetonitrile as the mobile phase (flow rate 0.8 mL min⁻¹). Detection took place with the photodiode array detector Varian ProStar and the wavelength at which the absorption was recorded was 285 nm. The total running time was 16 min and the retention time of DCP was 12.4 min.