The generation of a tunable laser emission in the vacuum ultraviolet and its application to supersonic jet/multiphoton ionization mass spectrometry

1999 ◽  
Vol 70 (8) ◽  
pp. 3254-3258 ◽  
Author(s):  
Tomohiro Uchimura ◽  
Takayuki Onoda ◽  
Cheng-Huang Lin ◽  
Totaro Imasaka
Keyword(s):  
Mass Spectrometry ◽  
Laser Emission ◽  
Vacuum Ultraviolet ◽  
Multiphoton Ionization ◽  
Supersonic Jet ◽  
Tunable Laser ◽  
Ionization Mass Spectrometry ◽  
Ionization Mass

Multiphoton Ionization Mass Spectrometry of Chlorophenols as Indicators for Dioxins

2003 ◽  
Vol 57 (4) ◽  
pp. 461-465 ◽  
Author(s):  
Tomohiro Uchimura ◽  
Klaus Hafner ◽  
Ralf Zimmermann ◽  
Totaro Imasaka
Keyword(s):  
Mass Spectrometry ◽  
Excited State ◽  
Molecular Beam ◽  
Multiphoton Ionization ◽  
Supersonic Jet ◽  
Flue Gases ◽  
Ionization Mass Spectrometry ◽  
Ionization Mass ◽  
Molecular Cooling ◽  
Supersonic Jet Expansion

Mono-, di- and trichlorophenols were measured using resonance-enhanced multiphoton ionization mass spectrometry (MPI-MS) combined with supersonic jet (SSJ) or effusive molecular beam (EMB) spectrometry. All mono- and dichlorophenols, except 2,6-dichlorophenol, provided sharp and structured MPI spectra for the S1←S0 transition. Selectivity and sensitivity were both enhanced when SSJ spectrometry was used, compared with EMB spectrometry, because of a narrower linewidth in the MPI spectrum, given by molecular cooling by supersonic jet expansion. The ionization efficiency decreased with increasing number of chlorine substituents for the chlorophenols, since they have shorter excited-state lifetimes and require three photons for ionization. Some of the chlorophenols, which are toxic themselves, have the potential for use as indicators for analysis of polychlorinated dibenzo- p-dioxin/dibenzofurans in flue gases emitted from an incinerator.

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