IN-SITU ANALYSIS OF ORGANIC MONOLAYERS AND THEIR REACTIVITY ON SINGLEMICROMETER-SIZED PARTICLES BY TIME-OF-FLIGHT SECONDARY-ION MASS-SPECTROMETRY

Time-of-flight secondary ion mass spectrometry (TOF-SIMS) was used to study submonolayers of organic compounds of environmental significance adsorbed on coal flyash particles. Through the use of mass-resolved s econdary ion images and mass spectra, chemical information on single p articles was obtained. For example, TOF-SIMS was capable of distinguis hing particles which had higher levels of adsorbed polycyclic organic matter (POM). For flyash particles coated with submonolayer coverages of benzo[e]pyrene, the carbonaceous fraction of these particles had mu ch higher coverages of the adsorbate than did particles from the miner al fraction. TOF-SIMS was also used to monitor reactions such as the p hotooxidation of benz[a]anthracene on individual particle surfaces. Be nz[a]anthracene-7,12-dione was formed during the initial 15 min of pho tolysis and gradually decayed with increased photolysis time.