Combustion and Other Studies with Tunable Synchrotron VUV Photoionization Mass Spectrometry

Traditional mass spectrometers with electron impact ionization are limited in their utility by fragmentation, limited electron energy resolution, and low ionization cross-section at chemically interesting ionization thresholds (6-14 eV). Synchrotron VUV photoionization is a kind of “soft” process, which is a universal and selective method for detecting both stable and radical species in flames. Isomers can be distinguished by measurement of photoionization efficiency spectra. Thus the synchrotron VUV photoionization combining with molecular-beam mass spectrometry is potentially a powerful tool for the study of formation mechanisms of PAHs and soot in combustion. Besides combustion study, some new experimental methods combining the tunable synchrotron VUV photoionization with different techniques have been developed recently at National Synchrotron Radiation Laboratory, Hefei, China. These new methods can be applied on studies of pyrolysis, low-temperature plasma diagnostic, biomolecule, drug discovery etc.