title: Real-time monitoring of monochlorinated benzene and polychlorinated biphenyls in the gas phase with on-line detection: High chemical selectivity of resonance-enhanced two-photon ionization.
abstract: The development of molecular spectroscopy has enabled us to select chlorinated aromatic hydrocarbons very rapidly. In particular, the laser ionization TOFMS (time-of-flight mass spectrometry) method is expected to be useful as an on-line, selective, and sensitive method. In the present work, real-time laser ionization TOFMS measurements were carried out on gaseous chlorinated aromatic hydrocarbons. The laser ionization method used resonance-enhanced two-photon ionization with the direct introduction of gas into the vacuum chamber. This method for analyzing aromatic hydrocarbons was developed using a pulsed supersonic molecular beam method. In the context of developing a highly selective and sensitive method, excitation of monochlorinated benzene at lambda = 263.07 nm was found to be effective in the wavelength region from 263 nm to 265 nm. Also the excitation of polychlorinated biphenyls at lambda = 266 nm was found to be substantially more effective than at lambda = 280, 300 or 320 nm. The achievable sensitivity for real-time (1 min) measurements using the laser ionization TOFMS technique was found to be in the ppbV range.
authors.affiliation: Nagasaki R&D Center, Mitsubishi Heavy Industries Ltd, Fukahori-machi, Nagasaki, Japan. shinsaku_dobashi@mhi.co.jp
authors.forename: Shinsaku
authors.initials: S
authors.lastname: Dobashi
authors.forename: Masaharu
authors.initials: M
authors.lastname: Kira
authors.forename: Ryuichiro
authors.initials: R
authors.lastname: Tanaka
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Izawa
authors.forename: Akihide
authors.initials: A
authors.lastname: Wada
authors.forename: Michikazu
authors.initials: M
authors.lastname: Hara