Determination of phenolic profiles in edibles oils by dispersive liquid-liquid microextraction-capillary zone electrophoresis

MONASTERIO, R.P.; FERNANDEZ, M. DE LOS A.; GOMEZ, F.J.V; SILVA, M.F.

Buenos Aires

Simposio; The 18th Latin-American Symposium on Biotechnology, Biomedical, Biopharmaceutical and Industrial Applications of Capillary Electrophoresis and Microchip Technology; 2012

Phenolic compounds can only be found in edible oils that require no refining process, such as olive oil. For this reason these oils are an important lipid source, frequently associated with a low incidence of cardiovascular diseases as well as antioxidant properties. There is important and proven scientific evidence that it has health benefits; that include reduction of risk factors for coronary heart disease and the prevention of several pathologies, including some types of cancer (1, 2). Indeed, these compounds extend olive oils shelf life by delaying oxidation reactions and improving some sensory properties including pungency, astringency, bitterness and flavor (1, 3). A dispersive liquid?liquid microextraction (DLLME) was developed for the selective extraction of phenolic compounds (caffeic, gallic, vanillic, syringic, p-coumaric, cinnamic acids and oleuropein, apigenin, luteolin, 3-hydroxytyrosol and tyrosol) in edible oil samples. The optimized extraction conditions for 20 g sample were: volume of extractant (boric acid 30 mM): 400 mL; volume of dispersive agent: 300 mL; vortex: 8 min; centrifugation: 3 min. The simultaneous determination of the phenolic extracts was investigated by CZE. Besides, an on-line staking sample preconcentration (water plug), allowed to improve the peaks shape and LODs. Separations were carried out on a bare fused-silica capillary (75 mm i.d. × 60 cm length) with 30 mM boric acid (pH 9.5) as BGE in the normal polarity mode, voltage 23 kV, temperature 30 ºC, injection time 3 s (30 mbar) and electropherograms were recorded at 200 nm. Under these conditions the phenolic compounds were successfully separated in less than 8 min. Finally, this methodology allows short time of sample preparation with low generation of wastes being a sustainable methodology. [1] Montealegre, C., Marina, M. L., García-Ruiz, C., Electrophoresis 2010, 31, 2218-2225. [2] Montealegre, C., Alegre, M. L. M., García-Ruiz, C., Journal of Agricultural and Food Chemistry 2010, 58, 28-38.