Component Analysis of Particulate Products in Electron Beam-Irradiated Xylene/Air Mixtures Using an Atmospheric Pressure Ionization Mass Spectrometer

摘要

Particulate and gaseous organics are formed,as transient products,from dilute concentrations of xylene in air under electron beam irradiation; however,the components of the particulate organic products and the particle formation process are unknown.In the present study,the component analysis of particulate products were performed employing an atmospheric pressure ionization mass spectrometer (APIMS) based on a temperature-programmed desorption method to identify the components of the particles from o-xylene as a function of their gasification temperatures.Ions of 139-203 u with a peak interval of the m/z of 16 u,the same as the value of O~+,were observed as vaporized particle components at correspondent temperatures.The ions of 43,47,61,97,111,135,and 139 u were detected as the vaporized components at 333 K.The ions of 155,171,and 187 u were observed at 363 K,besides that of 203 u at 393 K.The ions of 392-421 u were also appreciable with peak heights of 10~(-2) order lower than those for the ions of 139-203 u at temperatures higher than 393 K.The gaseous products in irradiated o-xylene/air mixtures were also analyzed with the APIMS.The ions with m/z lower than 139 u were detected as gaseous products.