title: Ultrasound-assisted emulsification-microextraction for the determination of phenolic compounds in olive oils.
abstract: A reliable, sensitive and effective method based on ultrasound-assisted emulsification-microextraction (USAEME) coupled to HPLC-DAD has been developed to identify and quantify several target phenolic compounds from extra virgin olive oils (EVOO). This approach is based on the emulsification of a microvolume of polar organic extractant in a non-polar liquid sample by ultrasound radiation and further separation of both liquid phases by centrifugation. The percentage of methanol/water (v/v) in the extractant, the volume of extractant, and the extraction time as three effective parameters on the extraction were optimised by a central composite design (Box-Behnken response surface) method. The optimised method presented recoveries in EVOO between 91% and 115% for the target analytes (except vanillin with 65%) and a satisfactory precision with relative standard deviations (RSD%) lower than 8.4% for repeatability and reproducibility. The method showed good linearity and limits of detection and quantification were in the range 0.001-0.14 and 0.004-0.47mg/kg, respectively. After method validation, it was successfully applied to the analysis of three EVOO samples. All target compounds were detected in all analysed samples. Tyrosol and hydroxytyrosol were the major phenolic compounds, followed by pinoresinol and luteolin.
authors.affiliation: Nutrition and Bromatology Group, Analytical and Food Chemistry Department, Faculty of Food Science and Technology, University of Vigo, Ourense Campus, E-32004 Ourense, Spain.
authors.forename: P
authors.initials: P
authors.lastname: Reboredo-Rodríguez
authors.affiliation: Nutrition and Bromatology Group, Analytical and Food Chemistry Department, Faculty of Food Science and Technology, University of Vigo, Ourense Campus, E-32004 Ourense, Spain.
authors.forename: L
authors.initials: L
authors.lastname: Rey-Salgueiro
authors.affiliation: Nutrition and Bromatology Group, Analytical and Food Chemistry Department, Faculty of Food Science and Technology, University of Vigo, Ourense Campus, E-32004 Ourense, Spain.
authors.forename: J
authors.initials: J
authors.lastname: Regueiro
authors.affiliation: Nutrition and Bromatology Group, Analytical and Food Chemistry Department, Faculty of Food Science and Technology, University of Vigo, Ourense Campus, E-32004 Ourense, Spain.
authors.forename: C
authors.initials: C
authors.lastname: González-Barreiro
authors.affiliation: Nutrition and Bromatology Group, Analytical and Food Chemistry Department, Faculty of Food Science and Technology, University of Vigo, Ourense Campus, E-32004 Ourense, Spain.
authors.forename: B
authors.initials: B
authors.lastname: Cancho-Grande
authors.affiliation: Nutrition and Bromatology Group, Analytical and Food Chemistry Department, Faculty of Food Science and Technology, University of Vigo, Ourense Campus, E-32004 Ourense, Spain. Electronic address: jsimal@uvigo.es.
authors.forename: J
authors.initials: J
authors.lastname: Simal-Gándara
mesh_terms: D057230:Limit of Detection; D059627:Liquid Phase Microextraction / Q000379:methods*; D000069463:Olive Oil; D010636:Phenols / Q000032:analysis / Q000302:isolation & purification*; D010938:Plant Oils / Q000737:chemistry*; D014465:Ultrasonics / Q000379:methods*
chemical_list: D000069463:Olive Oil; D010636:Phenols; D010938:Plant Oils
keywords: Liquid chromatography; Phenolic compounds; Ultrasound-assisted emulsification–microextraction; Virgin olive oil