Original PaperSimultaneous extraction of tocotrienols and tocopherols from cereals using pressurized liquid extraction prior to LC determination Tocopherols and tocotrienols have been simultaneously determined in food samples using a rapid and simple analytical method including pressurized liquid extraction (PLE) and LC with electrochemical detection. Separation was carried out on a Phenomenex Synergi 4 lm Hydro-RP 80A column, using a solution of 2.5 mM acetic acid/sodium acetate in methanol/water (99:1, v/v) as mobile phase at a flow rate of 1.0 mL/min. Column temperature was maintained at 308C. Detection was performed by coulometric detection at 500 mV except for (b+c)-tocotrienol, in wheat and rye samples, which was at +350 mV. A palm oil containing a relatively large amount of c-tocotrienol and lower concentrations of a-and d-tocotrienols and a-and c-tocopherols was used to provide reference retention times for the tocotrienols. Analyte quantification was performed using the external standard method. The calibration equations of tocopherols were used to quantify both tocopherols and their corresponding tocotrienols. The extraction recoveries obtained using the optimized PLE conditions were in the 80 -114% range, with RSDs lower than 15%. The method was successfully applied to the determination of tocotrienols and tocopherols in cereal (wheat, rye, barley, maize and oat) and palm oil samples. IntroductionTocopherols (a-, b-, c-and d-T) and tocotrienols (a-, b-, cand d-T3) are lipophilic antioxidants, all of them designed vitamin E. They consist of a polar chromanol group and an apolar isoprenoid side chain. The isoprenoid tail of tocotrienols contains three unsaturated bonds, while the tail of tocopherols is fully saturated. The highest amounts of vitamin E are found in cereals and vegetable oils. Most vegetable oils and biological fluids contain varying amounts of tocopherols. Nevertheless, tocotrienols can be found in palm oil, coconut oil, and cereal grains such as wheat, rye, oats and barley. Functionally, vitamin E is a potent biological antioxidant that protects cytoplasmic membranes from oxidation and guards low-density lipoproteins from dangerous lipid peroxidation processes. Its antioxidant capacity and its ability to act as a free radical scavenger can reduce the risk of cancer and delay the progression of precancerous lesions. Tocotrienols reduce plasma cholesterol levels, as well as other lipids and non-lipids related to risk factors for cardiovascular diseases. In the field of cancer chemotherapy, tocotrienols display better antitumor activity than a-T [1]. Some authors state that tocotrienols have powerful neuroprotective, antioxidant, anti-cancer and cholesterol-lowering properties that often differ from the properties of tocopherols [2]. Since these eight vitamers have different antioxidant and biological activities, it is necessary to have separate quantitative data about each of them.The separation and quantification of tocotrienols and tocopherols are carried out mainly by chromatography, ...