title: A determination method of pristine multiwall carbon nanotubes in rat lungs after intratracheal instillation exposure by combustive oxidation-nondispersive infrared analysis.
abstract: This paper describes a method for determination of multiwall carbon nanotubes (MWCNTs) in rat lungs after intratracheal instillation exposure. The MWCNTs were quantitatively decomposed to CO(2) by combustive oxidation and were then determined by non-dispersive infrared analysis. Samples were pretreated by acid digestion, muffle ashing and in situ preheating to remove interferences due to coexisting biological carbon from the lung tissue sample, while preserving the MWCNTs as in its their original form. The preservation was confirmed by transmission electron microscopic observation of the pretreated samples of exposed lung tissues and by the fact that the recoveries of MWCNTs spiked to the lung tissues were close to 100%. The detection limit for MWCNTs obtained by the proposed method was 0.30 μg and the repeatability as expressed by the relative standard deviation was 5.6% (n=4). The method was sufficiently sensitive and precise to apply to real samples of rat lung to investigate the in vivo persistence of intratracheally instilled MWCNTs. To our knowledge, this is the first report of this type of sample pretreatment and direct determination of pristine MWCNTs without modification or tagging. Conventional indirect methods use tagging with other compounds or metal impurities in the CNTs for detection, and the detachment of these tags can increase uncertainties in the determination of the CNTs. The tags can also change how the CNTs persist in vivo, which can lead to an incorrect understanding of the persistence of pristine CNTs in vivo.
authors.affiliation: Research Institute for Environmental Management Technology, National Institute of Advanced Industrial Science and Technology (AIST), 16-1 Onogawa, Tsukuba, Ibaraki 305-8569, Japan.
authors.forename: Moritaka
authors.initials: M
authors.lastname: Tamura
authors.forename: Masaharu
authors.initials: M
authors.lastname: Inada
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Nakazato
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Yamamoto
authors.forename: Shigehisa
authors.initials: S
authors.lastname: Endo
authors.forename: Kunio
authors.initials: K
authors.lastname: Uchida
authors.forename: Masanori
authors.initials: M
authors.lastname: Horie
authors.forename: Hiroko
authors.initials: H
authors.lastname: Fukui
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Iwahashi
authors.forename: Norihiro
authors.initials: N
authors.lastname: Kobayashi
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Morimoto
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Tao
mesh_terms: D000818:Animals; D004333:Drug Administration Routes; D057230:Limit of Detection; D008168:Lung / Q000378:metabolism*; D046529:Microscopy, Electron, Transmission; D037742:Nanotubes, Carbon; D010084:Oxidation-Reduction; D051381:Rats; D014132:Trachea
chemical_list: D037742:Nanotubes, Carbon