title: Post-source decay of alkylated and functionalized polycyclic aromatic compounds.
abstract: Post-source decay (PSD) is a valuable tool for providing structural information from large molecules by time-of-flight mass spectrometry (TOFMS). We used PSD to obtain this type of data from small molecules in the laser desorption/ionization (LDI) study of diesel engine exhaust particles. As the original nitrogen laser (lambda = 337 nm, E = 3.5 eV/photon) of our TOF mass spectrometer does not yield sufficient energy to ionize polycyclic aromatic hydrocarbons (PAHs), a second laser with a shorter wavelength has been coupled to the instrument. The fourth harmonic of a Nd:YAG laser (lambda = 266 nm, 4.6 eV/photon) has been chosen to achieve two-photon single-step desorption/ionization of PAHs. The PSD fragmentation of functionalized, alkylated and sulfur PAHs is discussed. Diesel engine exhaust particles are also studied as an example of a real complex sample. This technique is presented herein as a way to identify small molecules in environmental samples. Information provided by LDI-PSD-TOFMS can be a way to distinguish pollutants with very close molecular weights even if the resolving power of a TOF mass spectrometer is not sufficient.
authors.affiliation: Laboratoire de Spectrométrie de Masse et de Chimie Laser, Université Paul Verlaine - Metz, 1 Bd Arago, 57078 Metz, Technopôle 2000 Cedex 03, France.
authors.forename: Gilles
authors.initials: G
authors.lastname: Frache
authors.forename: Gabriel
authors.initials: G
authors.lastname: Krier
authors.forename: Lionel
authors.initials: L
authors.lastname: Vernex-Loset
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Muller
authors.forename: Pascal
authors.initials: P
authors.lastname: Manuelli
mesh_terms: D000478:Alkylation; D004784:Environmental Monitoring / Q000379:methods*; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D007700:Kinetics; D010084:Oxidation-Reduction; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis* / Q000737:chemistry*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D001335:Vehicle Emissions / Q000032:analysis*
chemical_list: D011084:Polycyclic Aromatic Hydrocarbons; D001335:Vehicle Emissions