Details

Autor(en) / Beteiligte

• Fang, Wenzheng
• Lei, Gong
• Shan, Xiaobin
• Liu, Fuyi
• Wang, Zhenya
• Sheng, Liusi

Titel

A VUV photoionization organic aerosol mass spectrometric study with synchrotron radiation

Ist Teil von

• Journal of electron spectroscopy and related phenomena, 2011-04, Vol.184 (3), p.129-133

Ort / Verlag

Elsevier B.V

Erscheinungsjahr

2011

Link zum Volltext

Quelle

Elsevier ScienceDirect Journals Complete

Beschreibungen/Notizen

• ▶ A photoionization aerosol time-of-flight mass spectrometer (ATOFMS) has been developed for on-line analysis of organic compounds in aerosol particles using tunable vacuum ultraviolet (VUV) synchrotron radiation. ▶ The degree of fragmentation of molecule can be controlled either by the heater temperature or by the photon energy. ▶ The direct determination of the IEs of benzopheneone (9.07 eV), salicylic acid (8.72 eV), and urea (9.85 eV) are measured from the photoionization efficiency spectra. ▶ The species can be identified by their molecular and fragment ions weights as well as by the comparisions between their theoretical and experimental ionization energies. A photoionization aerosol time-of-flight mass spectrometer (ATOFMS) has been developed for on-line analysis of organic compounds in aerosol particles using tunable vacuum ultraviolet (VUV) synchrotron radiation. Aerosol particles can be sampled directly from atmospheric pressure and are focused through an aerodynamic lens assembly into the mass spectrometer. The particles are vaporized when they impact on a heater, and then the nascent vapor is softly photoionized by synchrotron radiation. The degree of fragmentation of molecule can be controlled either by the heater temperature or by the photon energy. Thus, fragment-free tunable VUV mass spectra are obtained by tuning the photon energy close to the ionization energies (IEs) of the sample molecules. The direct determination of the IEs of benzophenone (9.07 eV), salicylic acid (8.72 eV), and urea (9.85 eV) are measured from the photoionization efficiency spectra with uncertainties of ±50 meV. Ab initio calculations have been employed to predict the theoretical ionization energy.