2.3.4. Tocols (tocopherols and tocotrienols) analysis
Analysis of tocols (tocopherols and tocotrienols) in oil of pine nut was carried out using “Shimadzu Prominence-I LC 2030C 3D Plus HPLC” according to TS ISO 9936 (2004) method. Depending on the tocols concentration, approximately 1 g of oil sample was weighed into a 20 mL test tube. A 10 mL of hexane was added and the tube was vortexed for 2 minutes to dissolve the sample. It was then filtered through a 0.45 µm nylon filter and added to a 1.5 mL vials [13, 14].