1987 Fiscal Year Final Research Report Summary
High sensitive determination by the use of laser multi-photon ionization.
| Project/Area Number |
60470067
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
工業分析化学
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| Research Institution | Kyushu University |
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Principal Investigator |
OGAWA Teiichiro Graduate School of Engineering Sciences, Kyushu University, 総合理工学研究科, 教授 (50028156)
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| Co-Investigator(Kenkyū-buntansha) |
YAMADA Sunao College of Liberal Arts, Kyushu University, 教養部, 助教授 (30136551)
NAGAMURA Toshihiko Graduate School of Engineering Sciences, Kyushu University, 総合理工学研究科, 助教授 (90117200)
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| Project Period (FY) |
1985 – 1987
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| Keywords | Laser / multi-photon ionization / High sensitive determination / Detection limit / Aromatic hydrocarbons / High-performance liquid chromatography / 高速流体クロマトグラフ / 表面 |
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| Research Abstract |
1. Analysis of the laser photoionization current.
The current signal of th aromatic molecules in solution consists of a fast signal of electrons and a slow signal of ionz. The current signal is large for those molecule with large molar absorptivities. Its laser wavelength dependence (two-photon ionization spectrum) shows structure similar to the absorption spectrum, but it increases in the shorter wavelength region due to the increase in the ionization efficiency for a larger excess energy.
2. High sensitive analysis in solution
The best wavength for a high sensitive determination has been decided by the use of the two-photon ionization spectrum of each molecule. The high seisitve detection of several aromatic hydrocarbons have been carried out in hexane. The detection limits and detection wavelengths are 20 ppt and 337 nm for pyrene, 50 ppt and 383 nm for perylene, and 20 ppt and 407 nm for naphthacene. The detection limits are considerably lower in polar solvents because of their large dark current.
3. High sensitive analysis in gas phase
The aromatic hydrocarbons in ambient nitrogen gas were detected with excitation by the second harmonics of the dye lasers. The detection limits are 9 ppb for benzene, 8 ppb for toluene, and 0.8 ppb for aniline. The solid aromatic hydrocarbons were determined by thermal evaporation techniques.
4. Other applications
The laser can be focused in a small spot and is convenient for an application to a detector of a high-performance liquid chromatography system. Also, a small amount of aromatic hydrocarbons on metal surface can be determined by the laser photoionization technique. Preliminary experiments on these subjects have been carried out.
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