title: Sample preparation improvement in polycyclic aromatic hydrocarbons determination in olive oils by gel permeation chromatography and liquid chromatography with fluorescence detection.
abstract: The determination of 15 polycyclic aromatic hydrocarbons (PAHs) in olive oil samples has been improved in order to obtain a fast methodology with a low limit of detection through the combination of liquid-liquid extraction with acetonitrile and preparative gel permeation chromatography (GPC) prior to the injection of purified extracts into a C18 column. Acetonitrile-water was used as the mobile phase with a gradient from 50 to 95%, w/w, acetonitrile in 30 min. The oven temperature was maintained at 15 degrees C, and fluorometric detection was made at a fixed excitation wavelength of 264 nm and variable, optimal emission wavelength for each analyte ranging from 352 nm for 11-H-benzo(b)fluorene to 500 nm for indeno(1,2,3-cd)pyrene. Recovery for all the compounds studied varied from 75 to 111%, and limit of detection values from 0.05 ng/g for benzo(k)fluoranthene to 0.48 ng/g for indeno(1,2,3-cd)pyrene, corresponding to 0.09 ng/g benzo(a)pyrene. Results were compared with those obtained by liquid-liquid extraction followed by a cleanup on silica and a direct GPC treatment of oil samples diluted in dichloromethane, 2 other methodologies that are appropriate for quantifying PAHs in olive oils. However, the proposed method improves the determination limits, reduces the time of analysis, and provides a highly stable baseline for sample chromatograms.
authors.affiliation: University of Valencia, Department of Analytical Chemistry, Research Building, 50 Dr. Moliner St, 46100 Burjassot, Valencia, Spain.
authors.forename: Sandra
authors.initials: S
authors.lastname: Martinez-López
authors.forename: Asuncion
authors.initials: A
authors.lastname: Morales-Noé
authors.forename: Agustin
authors.initials: A
authors.lastname: Pastor-Garcia
authors.forename: Angel
authors.initials: A
authors.lastname: Morales-Rubio
authors.forename: Miguel
authors.initials: M
authors.lastname: de la Guardia
mesh_terms: D000097:Acetonitriles / Q000494:pharmacology; D002623:Chemistry Techniques, Analytical / Q000379:methods*; D002850:Chromatography, Gel / Q000379:methods*; D002851:Chromatography, High Pressure Liquid; D002853:Chromatography, Liquid / Q000379:methods*; D005449:Fluorenes / Q000032:analysis; D005470:Fluorometry; D008752:Methylene Chloride / Q000032:analysis; D000069463:Olive Oil; D010938:Plant Oils / Q000032:analysis*; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis*; D012822:Silicon Dioxide / Q000032:analysis; D013050:Spectrometry, Fluorescence / Q000379:methods*; D013696:Temperature; D013997:Time Factors; D014465:Ultrasonics
chemical_list: D000097:Acetonitriles; D005449:Fluorenes; D000069463:Olive Oil; D010938:Plant Oils; D011084:Polycyclic Aromatic Hydrocarbons; D008752:Methylene Chloride; D012822:Silicon Dioxide; C022921:benzo(k)fluoranthene; C032159:acetonitrile