title: Extraction of polycyclic aromatic hydrocarbons from cookies: a comparative study of ultrasound and microwave-assisted procedures.
abstract: The chromatographic determination of 15 polycyclic aromatic hydrocarbons (PAHs) in cookies has been improved in order to obtain a fast method with a low limit of detection through the combination of microwave-assisted extraction (MAE), oil saponification and solid-phase extraction clean-up before the injection of purified extracts in a C18 201TP52 (5 microm, 250 x 2.1 mm) column. Using acetonitrile-water as mobile phase, with a 50% to 95% w/w acetonitrile gradient for a fixed flow of 0.250 ml min(-1), 15 PAHs were separated in 45 min. The column temperature was maintained at 15 degrees C; and fluorimetric detection was made at a fixed excitation wavelength of 264 nm and emission measurements at the best wavelength for each analyte, from 352 nm for 11H-benzo[b]fluorene to 500 nm for indeno[1,2,3-c,d]pyrene. Recoveries for all 15 PAHs varied between 96 +/- 4 and 105% +/- 4%; and the limits of detection ranged from 0.015 ng g(-1) for chrysene to 0.7 ng g(-1) for phenantrene. Results were compared with those obtained by conventional Soxhlet extraction during 8-h refluxing with toluene, demonstrating that the methodology proposed is appropriate to quantify PAHs in cookies. Furthermore, the microwave-assisted method was faster and used less solvent than the conventional and ultrasound-assisted methods. The extraction time was reduced to 9 min compared with the 8 h required for Soxhlet extraction and 60 min required for ultrasound-assisted treatment, and the solvent consumption has been reduced to 25 ml compared with the 155 and 90 ml required using Soxhlet and ultrasound, respectively.
authors.affiliation: Department of Analytical Chemistry, University of Valencia, Valencia, Spain.
authors.forename: G F
authors.initials: GF
authors.lastname: Hernández-Póveda
authors.forename: A
authors.initials: A
authors.lastname: Morales-Rubio
authors.forename: A
authors.initials: A
authors.lastname: Pastor-García
authors.forename: M
authors.initials: M
authors.lastname: De La Guardia
mesh_terms: D002851:Chromatography, High Pressure Liquid; D005433:Flour; D005470:Fluorometry; D005506:Food Contamination / Q000032:analysis*; D019649:Food Industry; D008872:Microwaves; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis*; D052616:Solid Phase Extraction / Q000379:methods; D014465:Ultrasonics
chemical_list: D011084:Polycyclic Aromatic Hydrocarbons