A VUV photoionization organic aerosol mass spectrometric study with synchrotron radiation

▶ 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.