TITLE Imaging Mass Spectrometry of ParticulateAssociated Polynuclear Aromatic Hydrocarbons AUTHOR(S) Michael J. Holland, Richard W. Linton, Joette L. Steger, Raymond G. Merrill, Greg S. Strossman, Thomas F. Fister and Robert W. Osom PERFORMING ORGANIZATION NAME AND ADDRESS Dept. Of Chemistry, CB# 3290, University of North Carolina, Chapel Hill, NC 275993290 SPONSORING AGENCY NAME AND ADDRESS National Exposure Research Laboratory Office of Research and Development U.S. Environmental Protection Agency Research Triangle Park, NC 27711 ABSTRACT TimeofFlight secondary ion mass spectrometry (TOFSIMS) was employed for the in situ investigation of PAHs on individual environmental particulate. TOFSIMS is a microprobe mass spectrometry technique capable of providing surface elemental and chemical information with lateral spatial resolutin <1 um. TOF SIMS analysis allows for the correlation of microscopic characteristics of different particulate, filter, and sorbent substrates with adsorbed species. Silver membrane and glass fiber filters loaded with coal flyash or silica gel were placed in a method 0010 spiking train and exposed to vapor phase benzo[a]anthracene, benzo[g,h,i]perylene or pyrene. TOFSIMS allowed surface chemical analysis of single particles on Ag filter media taken directly from the Method 0010 sampling train, without additional sample preparation. Secondary ion images indicated that benzo[a]anthracene is found primarily on the filter media and not on the flyash surfaces, and is of interest with respect to the elucidation of sampling artifacts. Particulate matter was also transferred to silicon wafers where native levels of diesel soot POM were imaged using TOFSIMS.