2 methyl 2 4 8 12 trimethyltridecyl chroman 6 ol tocol

Tocopherols (α-, β-, γ-, and δ-) and tocotrienols (α-, β-, γ-, and δ-) were acquired from Supelco (Bellefonte PA, USA,) and Larodan AB (Malmö, Sweden). Retinyl palmitate and retinol were obtained from Fluka (Buchs, Switzerland) and pheophytin was acquired from DHI (Hørsholm, Denmark). The 2-Methyl-2-(4,8,12-trimethyltridecyl)-chroman-6-ol (tocol) (Matreya Inc., Pleasant Gap, PA, USA) was used as internal standard (IS₁) for fluorescence analysis and trans-apo-8′-carotenal (Fluka, Seelze, Germany) was used as internal standard (IS2) for UV/Vis analysis. All remaining individual standards used for spectrophotometric and chromatographic analyses were of analytical reagent grade and obtained from Sigma-Aldrich (Steinheim am Albuch, Germany). All other reagents and solvents were of analytical or HPLC grade. Ultrapure water (18.2 MW cm resistivity) was used to prepare all the aqueous solutions and was produced using a Simplicity 185 water purification system (Millipore, Molsheim, France).

The reagents used in this study (analytical or higher grade) were from Sigma–Aldrich (St. Louis, MO, USA) and Merck (Darmstadt, Germany): ether petroleum, hexane, ether, acetone, isooctane and ethyl acetate. Tetrahydrofuran THF, heptane, n-hexane and diethyl ether were HPLC grade from the same suppliers. Silica cartridges for SPE were Sep-Pak columns supplied by Waters (Supelco, Bellefonte, PA, USA). The internal standard used for polar compounds quantification (monostearin) was obtained from Supelco (Bellefonte, PA, USA). Free stable DPPH radical, gallic acid and sterols standards were purchased from Sigma–Aldrich (St. Louis, MO, USA). Certified fatty acids methyl ester mixture (Supelco 37 Component FAME Mix, Supelco, Bellefonte, PA, USA) was from Supelco (Trace CERT, Bellefonte, PA, USA) as was γ-Tocopherol. The internal standard [2-Methyl-2-(4,8,12-trimethyltridecyl)-chroman-6-ol(tocol)] was purchased from Matreya Inc. (State College, PA, USA).