PERCI Aerosol Mass Spectrometry

The PERCI Aerosol Mass Spectrometer (AMS) consists of 4 main components: 1) Particle inlet; 2.) Particle Vaporization source; 3) PERCI source; and, 4) Time-of-Flight MS. The particle inlet is used to concentrate aerosol particles (in the air sample) with respect to the gas phase while decreasing the sample pressure from atmospheric pressure to about 10^-6 mbar. Under given operating conditions, the particle inlet may also be used to deliver only particles of one given diameter to the analytical zone of the instrument. After the particles are focused, they enter the vaporization and ionization region. The particles are thermally vaporized and the molecular components ionized for mass analysis by the reflectron time-of-flight mass spectrometer. The minimal molecular fragmentation caused during ionization allows for easy identification of the components of even the most complex organic particles. The adaptation of PERCI to AMS has been applied to the heterogeneous reaction of gas phase ozone with oleic acid particles and has provided new insights into this well-studied model system.