title: Determination of 4-tert.-octylphenol and 4-nonylphenol in laboratory animal feed sample by stir bar sorptive extraction followed by liquid desorption and column-switching liquid chromatography-mass spectrometry with solid-phase extraction.
abstract: A novel analytical method has been developed for the determination of 4-tert.-octylphenol (OP) and 4-nonylphenol (NP) in laboratory animal feed samples, which involves stir bar sorptive extraction (SBSE) followed by liquid desorption (LD) and column-switching liquid chromatography-mass spectrometry (CS-LC-MS) with solid-phase extraction (SPE). The method required correction by stable isotopically labeled surrogate standards, deuterium 4-tert.-octylphenol (OP-d) and [2H5] 4-(1-methyl)octylphenol (m-OP-d5). A feed sample was homogenized with methanol by ultrasonication. After centrifugation, the supernatant was subjected to extraction for 120 min at room temperature (25 degrees C) using a stir bar coated with polydimethylsiloxane. After the extraction, the analyte was desorbed from the stir bar by LD using acetonitrile. Then, the liquid sample was analyzed by CS-LC-MS with SPE. The average recoveries from laboratory feed samples spiked with OP and NP at 20 ng g(-1) were 99.5 and 103.8%, respectively, with correction using the added surrogate standards. The limits of quantification were 1 ng g(-1) for OP and 5 ng g(-1) for NP in feed sample. The measurement of OP and NP in commercial laboratory animal feed samples resulted in the detection of sub ng g(-1) NP
authors.affiliation: Department of Analytical Chemistry, Faculty of Pharmaceutical Sciences, Hoshi University, 2-4-41 Ebara, Shinagawa-ku, Tokyo 142-8501, Japan.
authors.forename: Migaku
authors.initials: M
authors.lastname: Kawaguchi
authors.forename: Shima
authors.initials: S
authors.lastname: Takahashi
authors.forename: Fumie
authors.initials: F
authors.lastname: Seshimo
authors.forename: Norihiro
authors.initials: N
authors.lastname: Sakui
authors.forename: Noriya
authors.initials: N
authors.lastname: Okanouchi
authors.forename: Rie
authors.initials: R
authors.lastname: Ito
authors.forename: Koichi
authors.initials: K
authors.lastname: Inoue
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Yoshimura
authors.forename: Shun-ichiro
authors.initials: S
authors.lastname: Izumi
authors.forename: Tsunehisa
authors.initials: T
authors.lastname: Makino
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Nakazawa
mesh_terms: D000821:Animal Feed / Q000032:analysis*; D002853:Chromatography, Liquid / Q000379:methods*; D013058:Mass Spectrometry / Q000379:methods*; D010636:Phenols / Q000032:analysis*
chemical_list: D010636:Phenols; C041594:4-nonylphenol; C105260:4-tert-octylphenol