title: Use of oleic-acid functionalized nanoparticles for the magnetic solid-phase microextraction of alkylphenols in fruit juices using liquid chromatography-tandem mass spectrometry.
abstract: Magnetic nanoparticles of cobalt ferrite with oleic acid as the surfactant (CoFe2O4/oleic acid) were used as sorbent material for the determination of alkylphenols in fruit juices. High sensitivity and specificity were achieved by liquid chromatography and detection using both diode-array (DAD) and electrospray-ion trap-tandem mass spectrometry (ESI-IT-MS/MS) in the selected reaction monitoring (SRM) mode of the negative fragment ions for alkylphenols (APs) and in positive mode for ethoxylate APs (APEOs). The optimized conditions for the different variables influencing the magnetic separation procedure were: mass of magnetic nanoparticles, 50mg, juice volume, 10mL diluted to 25mL with water, pH 6, stirring for 10min at room temperature, separation with an external neodymium magnet, desorption with 3mL of methanol and orbital shaking for 5min. The enriched organic phase was evaporated and reconstituted with 100µL acetonitrile before injecting 30µL into a liquid chromatograph with a mobile phase composed of acetonitrile/0.1% (v/v) formic acid under gradient elution. Quantification limits were in the range 3.6 to 125ngmL(-1). The recoveries obtained were in the 91-119% range, with RSDs lower than 14%. The ESI-MS/MS spectra permitted the correct identification of both APs and APEOs in the fruit juice samples.
authors.affiliation: Department of Analytical Chemistry, Faculty of Chemistry, Regional Campus of International Excellence "Campus Mare Nostrum", University of Murcia, E-30100 Murcia, Spain.
authors.forename: Pilar
authors.initials: P
authors.lastname: Viñas
authors.affiliation: Department of Analytical Chemistry, Faculty of Chemistry, Regional Campus of International Excellence "Campus Mare Nostrum", University of Murcia, E-30100 Murcia, Spain.
authors.forename: Marta
authors.initials: M
authors.lastname: Pastor-Belda
authors.affiliation: Department of Analytical Chemistry, Faculty of Chemistry, Regional Campus of International Excellence "Campus Mare Nostrum", University of Murcia, E-30100 Murcia, Spain.
authors.forename: Aitor
authors.initials: A
authors.lastname: Torres
authors.affiliation: Department of Analytical Chemistry, Faculty of Chemistry, Regional Campus of International Excellence "Campus Mare Nostrum", University of Murcia, E-30100 Murcia, Spain.
authors.forename: Natalia
authors.initials: N
authors.lastname: Campillo
authors.affiliation: Department of Analytical Chemistry, Faculty of Chemistry, Regional Campus of International Excellence "Campus Mare Nostrum", University of Murcia, E-30100 Murcia, Spain. Electronic address: hcordoba@um.es.
authors.forename: Manuel
authors.initials: M
authors.lastname: Hernández-Córdoba
mesh_terms: D000097:Acetonitriles / Q000737:chemistry; D000327:Adsorption; D002853:Chromatography, Liquid / Q000379:methods*; D005561:Formates / Q000737:chemistry; D000067030:Fruit and Vegetable Juices / Q000032:analysis*; D006863:Hydrogen-Ion Concentration; D008280:Magnetics; D000432:Methanol / Q000737:chemistry; D053758:Nanoparticles / Q000737:chemistry*; D009354:Neodymium / Q000737:chemistry; D019301:Oleic Acid / Q000737:chemistry*; D010636:Phenols / Q000032:analysis* / Q000737:chemistry / Q000302:isolation & purification; D015203:Reproducibility of Results; D052617:Solid Phase Microextraction / Q000379:methods*; D021241:Spectrometry, Mass, Electrospray Ionization; D053719:Tandem Mass Spectrometry / Q000379:methods*; D014867:Water / Q000737:chemistry
chemical_list: D000097:Acetonitriles; D005561:Formates; D010636:Phenols; D014867:Water; C030544:formic acid; D009354:Neodymium; D019301:Oleic Acid; D000432:Methanol; C032159:acetonitrile
keywords: Alkylphenol ethoxylates; Alkylphenols; Cobalt ferrite/oleic acid nanoparticles; Fruit juices; LC-ESI-IT-MS/MS; Magnetic solid-phase microextraction