Resonance-Enhanced Multiphoton Ionization and VUV-Single Photon Ionization as Soft and Selective Laser Ionization Methods for On-Line Time-of-Flight Mass Spectrometry: Investigation of the Pyrolysis o
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- 作者：L. Cao ; F. Mü ; hlberger ; T. Adam ; T. Streibel ; H. Z. Wang ; A. Kettrup ; and R. Zimmermann
- 刊名：Analytical Chemistry
- 出版年：2003
- 出版时间：November 1, 2003
- 年：2003
- 卷：75
- 期：21
- 页码：5639 - 5645
- 全文大小：370K
- 年卷期：v.75,no.21(November 1, 2003)
- ISSN：1520-6882
文摘
A newly conceived compact and mobile time-of flight massspectrometer (TOFMS) for real-time monitoring of highlycomplex gas mixtures is presented. The device utilizes twoselective and sensitive soft ionization techniques, viz.,resonance-enhanced multiphoton ionization (REMPI) andsingle-photon ionization (SPI) in a (quasi)-simultaneousmode. Both methods allow a fragmentationless ionization.The REMPI method selectively addresses aromatic species, while with SPI applying vacuum ultaviolet light (118nm) in principle all compounds with an ionization potential below 10.5 eV are accessible. This provides comprehensive information of the chemical composition of complex matrixes. The combustion and pyrolysis behavior offive organic materials typically used in steel processingin China was studied. The trace amounts of organiccompounds in the gas phase during combustion andpyrolysis were monitored selectively and sensitively byreal-time SPI/REMPI-TOFMS. The measurements werecarried out at several constant temperatures in the rangefrom 300 to 1190 
C in both synthetic air and nitrogen.Timely resolved mass spectra reveal the formation andsubsequent growth of aromatic molecules. At lower temperatures, highly alkylated PAHs predominate, while attemperatures above 800 C, the more stable benzene andPAHs without side chains prevail. Potential hyphenationof SPI/REMPI-TOFMS to methods of thermal analysis isdiscussed.
C in both synthetic air and nitrogen.Timely resolved mass spectra reveal the formation andsubsequent growth of aromatic molecules. At lower temperatures, highly alkylated PAHs predominate, while attemperatures above 800 C, the more stable benzene andPAHs without side chains prevail. Potential hyphenationof SPI/REMPI-TOFMS to methods of thermal analysis isdiscussed.