Author
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Abidi, Sharon |
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Submitted to: International Symposium on High Performance Liquid Phase Separations
Publication Type: Proceedings Publication Acceptance Date: 3/1/2003 Publication Date: 3/1/2003 Citation: ABIDI, S.L. CAPILLARY ELECTROCHROMATOGRAPHIC STUDY OF ANTIOXIDATIVE MINOR OIL CONSTITUENTS AND RELATED TOCOPHEROLQUINONES IN FRYING OILS. INTERNATIONAL SYMPOSIUM ON HIGH PERFORMANCE LIQUID PHASE SEPARATIONS. 2003. Abstracts. p.57. Interpretive Summary:
Technical Abstract: Vitamin E-active antioxidants are important minor constituents of vegetable oils for the inhibition of lipid peroxidation. The content and composition of the antioxidant components affect oil properties, quality and stability. In frying oils, these substances partially convert to quinonoidal oxidation products depending on heating duration and the nature of food media. We wish to report results of a study on simultaneous evaluation of tocopherols (T) and tocopherolquinones (TQ) in frying oils by capillary electrochromatography (CEC)-photodiode array detection. Prior to CEC assays, oil samples spiked with an internal standard were extracted with methanol for the enrichment of the title analytes. The CEC system employed a capillary column (25 cm x 75 um I.D.) custom packed with 3-um pentafluorophenylsilica (PFPS) or polymeric 3-um triacontylsilica (C30). Unless otherwise specified, the voltage, temperature, and electrokinetic-injection settings were maintained at 25 kV, 30 deg.C, and 10 kV/10s, respectively. The detector was set at 280 nm for monitoring standard mixtures and at 275-295 nm for sample quantitation. Optimization of CEC parameters and mobile phases of acetonitrile, methanol, and 25 mM tris (hydroxymethyl) aminomethane buffers yielded base-line resolution of all eight components of tocopherols and the corresponding oxidation products. CEC with the PFPS column led to an elution order consistent with that of increasing analyte hydrophobicity normally observed in a reversed-phase system: delta-TQ |
