ガス分析用大気圧ペニングイオン源の開発

概要

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A direct gas introduction type atmospheric pressure Penning ionization source for on-site analysis of environmental organic pollutants was developed. The long-lived metastable argon atoms Ar* (3P2 and 3P0) were utilized for Penning ionization. As the excitation energies of Ar* are 11.5 eV (3P2) and 11.8 eV (3P0), the major components of air such as N2, O2, CO2, CO, and H2O are not ionized with Ar* but most of the organic compounds can be ionized. Atmospheric pressure Penning ionization mass spectra of all samples studied in our experiment showed abundant molecular-related ions (M+, [M+H]+, and [M-H]+) as base peaks. In the mass spectra of sample gases (M) mixed with methanol, intense ion [M+CH3]+ was observed in addition to [M+H]+ and [2M+H]+. The appearance of [M+CH3]+ is due to the occurrence of the methyl cation transfer reaction, CH3OH2++M→CH3+M+H2O.
日本質量分析学会の論文
2004-06-01