Laser mass spectrometry is a newly developed method for pollutant detection. It combines resonance-enhanced multiphoton ionization (REMPI) and time-of-flight mass spectro- metry (TOF-MS). It may detect pollutants with...Laser mass spectrometry is a newly developed method for pollutant detection. It combines resonance-enhanced multiphoton ionization (REMPI) and time-of-flight mass spectro- metry (TOF-MS). It may detect pollutants with high sensitivity, high selectivity and in a multi-component way. In this note, laser mass spectrometry was used to detect the pollutants in exhaust gases from vehicles. With one-color REMPI (at 266 nm), several aromatic hydrocarbons, including benzene, toluene, xylene, C3-benzene, etc., were detected. These substances were selectively ionized by (1+1) REMPI and their mass resolution was detected by a TOF mass spectrometer. And a quantitative analysis was achieved.展开更多
Organic pollution has been gaining more and more attention.Yet,at present the determination of virtually all of them,including polycyclic aromatic carbons (PAHs),the largest single class of chemical carcinogens known ...Organic pollution has been gaining more and more attention.Yet,at present the determination of virtually all of them,including polycyclic aromatic carbons (PAHs),the largest single class of chemical carcinogens known today,is made via pre-purification and pre-concentration.The major problems are complexity and time-consuming,thus,no ideal real-time on-line monitoring can be done.Laser mass spectrometry combines UV spectroscopy and time-of-flight mass spectrometry (TOF-MS) through resonance-enhanced multiphoton ionization (REMPI).It is characteristic of high sensitivity,high selectivity and rapidity.In this paper,after its principles,a small mobile laser mass spectrometer,in which a mini-excimer (KrF,248 nm) laser was used,is introduced.Real-time analysis of vehicle exhaust gas was made using this instrument,and the results showed some advantages over traditional methods:multicomponent detection,including benzene,toluene,xylene,C3-benzene,naphthalene,and methyl-naphthalene; high sensitivity (100 ppb);high time-resolution (0.1 s);and no need for pre-purification or pre-concentration of samples.展开更多
The two-photon resonance-enhanced multiphoton ionization spectrum between 285 and288.5 nm of the band of CF radical is reported. The band isrotationally analyzed, and the spectroscopic constants of the state are first...The two-photon resonance-enhanced multiphoton ionization spectrum between 285 and288.5 nm of the band of CF radical is reported. The band isrotationally analyzed, and the spectroscopic constants of the state are first derived:σ0 = 69566.38±0.52 cm-1, A’v= 46.4±0.3 cm-1, B’v= 2.565±0.017 cm-1, D’V= (8.6±1.2)×10-6cm-1.展开更多
文摘Laser mass spectrometry is a newly developed method for pollutant detection. It combines resonance-enhanced multiphoton ionization (REMPI) and time-of-flight mass spectro- metry (TOF-MS). It may detect pollutants with high sensitivity, high selectivity and in a multi-component way. In this note, laser mass spectrometry was used to detect the pollutants in exhaust gases from vehicles. With one-color REMPI (at 266 nm), several aromatic hydrocarbons, including benzene, toluene, xylene, C3-benzene, etc., were detected. These substances were selectively ionized by (1+1) REMPI and their mass resolution was detected by a TOF mass spectrometer. And a quantitative analysis was achieved.
基金Wei Jie wishes to thank Prof. U. Boesl in Munich Technical University for the discussion with him about the design of the mobile laser mass spectrometer.
文摘Organic pollution has been gaining more and more attention.Yet,at present the determination of virtually all of them,including polycyclic aromatic carbons (PAHs),the largest single class of chemical carcinogens known today,is made via pre-purification and pre-concentration.The major problems are complexity and time-consuming,thus,no ideal real-time on-line monitoring can be done.Laser mass spectrometry combines UV spectroscopy and time-of-flight mass spectrometry (TOF-MS) through resonance-enhanced multiphoton ionization (REMPI).It is characteristic of high sensitivity,high selectivity and rapidity.In this paper,after its principles,a small mobile laser mass spectrometer,in which a mini-excimer (KrF,248 nm) laser was used,is introduced.Real-time analysis of vehicle exhaust gas was made using this instrument,and the results showed some advantages over traditional methods:multicomponent detection,including benzene,toluene,xylene,C3-benzene,naphthalene,and methyl-naphthalene; high sensitivity (100 ppb);high time-resolution (0.1 s);and no need for pre-purification or pre-concentration of samples.
文摘The two-photon resonance-enhanced multiphoton ionization spectrum between 285 and288.5 nm of the band of CF radical is reported. The band isrotationally analyzed, and the spectroscopic constants of the state are first derived:σ0 = 69566.38±0.52 cm-1, A’v= 46.4±0.3 cm-1, B’v= 2.565±0.017 cm-1, D’V= (8.6±1.2)×10-6cm-1.
