Simultaneous Determination Of Chlorophylls, Pheophytins, Beta-Carotene, Tocopherols, And Tocotienols In Olive And Soybean Oils By High-Performance Liquid Chromatography

A high-performance liquid chromatographic method is described for the simultaneous measurement of chlorophylls, pheophytins, beta-carotene, tocopherols, and tocotrienols in vegetable oils using 2 spectrophotometers in series and 1 normal-phase silica column. Oil samples were diluted in the mobile phase, isopropanol-hexane (1.5:98.5 vol/vol), and injected directly onto the column. A programmable UV/Vis spectrophotometer was used to measure chlorophylls a and b, pheophytins a and b, and beta-carotene at their appropriate absorption maxima (430, 452, 409, 433, and 452 nm, respectively). alpha-, gamma-, and delta-tocopherols and alpha-, gamma-, and delta-tocotrienols were measured by fluorescence at 295-nm excitation and 330-nm emission. Samples of virgin olive oil, soybean oil, and palm oil were analyzed.