Progress in vacuum ultraviolet photoionization mass spectrometry and application research of Hefei Research Institute

[ China Instrument Network Instrument Development ] Recently, Zhang Weijun, a researcher at the Anhui Institute of Optics and Fine Mechanics, Institute of Material Science, Chinese Academy of Sciences, made new progress in vacuum ultraviolet photoionization mass spectrometry and application research of free radical reaction kinetics. A vacuum ultraviolet photoionization time-of-flight mass spectrometer with high sensitivity for study of gas phase radical reaction in flow tube is published online in the international journal International Journal of Chemical Kinetics (DOI: 10.1002/kin.21241).

Figure 1. Vacuum ultraviolet photoionization time-of-flight mass spectrometer, combined with microwave discharge flow tube device to study atmospheric free radical reaction

Figure 2. (a) High resolution mass spectrum of benzene, toluene and xylene (M/ΔM = 2100); (b) Photoionization mass spectrum of methyl radical (LOD = 3 ppb).

The concentration of free radicals in the atmosphere is low, the lifespan is short, and the chemical activity is strong. As a reaction intermediate, it plays a key role in the atmospheric oxidation process. It is of great significance to carry out research on key chemical reactions of free radicals to reveal the oxidative properties of the atmosphere and the causes of pollution. Among them, the comprehensive detection of free radical reaction species (reactants, transient intermediates and reaction products, etc.) and the identification of isomers with different structures have been hot and difficult issues in this research field.

Tang Xiaofeng, an associate researcher of the research group, further developed vacuum ultraviolet photoionization mass spectrometry technology through the ingenious design of a new iontophoreser. Combined with the self-developed high-resolution, high-sensitivity small-reflection time-of-flight mass spectrometer, not only the free radicals in the flow reaction system were realized. The high-sensitivity mass spectrometry has reached the advanced level among international peers. At the same time, using synchrotron radiation as the ionization source, the full-scale detection of free radical reaction species was realized by vacuum ultraviolet photoionization mass spectrometry, and the photoionization efficiency spectrum was used to distinguish the same efficiently. Isomers.

The research work was supported by the National Key R&D Program, the National Natural Science Foundation and the Chinese Academy of Sciences' International Cooperation Key Project.

(Original title: Hefei Research Institute made progress in vacuum ultraviolet photoionization mass spectrometry and application research)