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
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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 <i>λ</i> = 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 <i>λ</i> = 266 nm was found to be substantially more effective than at <i>λ</i> = 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.
- Analytical Sciences
Analytical Sciences 22(4), 603-606, 2006-04-10
The Japan Society for Analytical Chemistry