title: Supercritical fluid clean-up of environmental samples for the analysis of polycyclic aromatic hydrocarbons using time-of-flight secondary ion mass spectrometry.
abstract: A novel sample-pretreatment method for time-of-flight secondary ion mass spectrometry (TOF-SIMS) was developed using supercritical fluid extraction (SFE). In SFE, the extraction efficiency of a certain organic matter is controlled by the pressure and temperature of supercritical CO2. Two-step SFE (1st step at 10 Mpa, 40 degrees C; 2nd step at 30 MPa, 120 degrees C) was applied to diesel exhaust particles containing many kinds of n-alkanes and aromatic species. n-Alkanes and polycyclic aromatic hydrocarbons (PAHs) were extracted in the 1st and 2nd steps, respectively. This selectivity was utilized for the sample preparation of TOF-SIMS analysis. Diesel exhaust particles after the 1st step of extraction were analyzed with TOF-SIMS, aiming at PAHs as analytical targets. The obtained spectrum was simplified, and mass peaks of individual PAHs were easily assigned, because unwanted compounds, like n-alkanes, were selectively removed by SFE. Furthermore, a simple calculation elucidated the outline of the spectrum.
authors.affiliation: Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan. tsakamo@iis.u-tokyo.ac.jp
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Sakamoto
authors.forename: Azusa
authors.initials: A
authors.lastname: Yamamoto
authors.forename: Masanori
authors.initials: M
authors.lastname: Owari
authors.forename: Yoshimasa
authors.initials: Y
authors.lastname: Nihei
mesh_terms: D000473:Alkanes / Q000032:analysis / Q000737:chemistry; D025924:Chromatography, Supercritical Fluid / Q000379:methods*; D004784:Environmental Monitoring / Q000379:methods; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis* / Q000737:chemistry; D018629:Spectrometry, Mass, Secondary Ion / Q000379:methods*; D001335:Vehicle Emissions / Q000032:analysis
chemical_list: D000473:Alkanes; D011084:Polycyclic Aromatic Hydrocarbons; D001335:Vehicle Emissions