Grantee Research Project Results
1997 Progress Report: Real-Time Analysis of PAH Bound to Size-Resolved Atmospheric Particles by Tandem Time of Flight Mass Spectrometers
EPA Grant Number: R825391Title: Real-Time Analysis of PAH Bound to Size-Resolved Atmospheric Particles by Tandem Time of Flight Mass Spectrometers
Investigators: Smith, Kenneth A.
Current Investigators: Smith, Kenneth A. , Worsnop, Douglas R.
Institution: Massachusetts Institute of Technology
EPA Project Officer: Hahn, Intaek
Project Period: October 1, 1996 through September 30, 1999 (Extended to November 30, 2000)
Project Period Covered by this Report: October 1, 1996 through September 30, 1997
Project Amount: $375,000
RFA: Exploratory Research - Air Engineering (1996) RFA Text | Recipients Lists
Research Category: Air Quality and Air Toxics , Land and Waste Management , Air , Safer Chemicals
Objective:
This research program is designed to develop and demonstrate an instrument that is capable of quantifying poly-cyclic aromatic hydrocarbon (PAH) associated with individual size-segregated atmospheric particles in real time. Our approach is to combine both particle sizing and a molecular composition analysis into a single measurement technique. PAH composition analysis is performed by vaporizing size-segregated PAH-containing particles on a heated filament. The PAH vapor is selectively photo-ionized by UV laser resonance enhanced multiphoton ionization (REMPI) and the molecular ions are classified using standard mass spectrometric analysis techniques.
During this reporting period we have demonstrated that composition of a PAH aerosol can be successfully detected by an aerosol mass spectrometer utilizing a heated filament to vaporize PAH particles. Fully developed, the final instrument will provide both particle size and composition classification for airborne particulate matter containing absorbed PAH material. The approach to sizing the PAH-containing aerosol has changed from the initially proposed technique that was based on electrostatic deflection of charged particles. The new sizing technique adopted utilizes a particle time-of-flight measurement and will simplifying the overall instrument since it eliminates a particle charging electron gun, its associated electronics and related calibration issues. The TOF sizing technique has been implemented and is currently being calibrated. The main task for the next reporting period is optimizing the coupling of an excimer laser to the vaporization cell and demonstrating selective ionization/detection of PAH material by REMPI. During this next stage of work we will continue to use a quadrupole mass spectrometer as a molecular ion detector. The final stage of this program will replace the QMS with a molecular TOF mass spectrometer providing complete mass spectral information for single particle vaporization events.
Journal Articles:
No journal articles submitted with this report: View all 10 publications for this projectSupplemental Keywords:
RFA, Scientific Discipline, Air, particulate matter, air toxics, Environmental Chemistry, mobile sources, Engineering, Chemistry, & Physics, monitoring, fate, particulates, aerosol particles, flight mass spectrometer, fine particles, atmospheric particles, air quality models, emissions measurement, fine particulates, ambient emissions, PAH, human exposure, combustion, ultraviolet excimer laser, vapor plumeProgress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.