HR: 1340h
AN: A33B-1186    [Abstracts]
TI: Characterization of the desorption step in a new two-laser desorption/ionization single- aerosol ion-trap mass-spectrometer
AU: * Simpson, E A
EM: esimpson@chem.ubc.ca
AF: University of British Columbia, Chemistry Department 6174 Universiy Blvd, Vancouver, BC V6T1Z3, Canada
AU: Campuzano Jost, P
EM: pcampuzano@chem.ubc.ca
AF: University of British Columbia, Chemistry Department 6174 Universiy Blvd, Vancouver, BC V6T1Z3, Canada
AU: Hanna, S J
EM: shanna@chem.ubc.ca
AF: University of British Columbia, Chemistry Department 6174 Universiy Blvd, Vancouver, BC V6T1Z3, Canada
AU: Robb, D B
EM: robb@chem.ubc.ca
AF: University of British Columbia, Chemistry Department 6174 Universiy Blvd, Vancouver, BC V6T1Z3, Canada
AU: Blades, M W
EM: blades@chem.ubc.ca
AF: University of British Columbia, Chemistry Department 6174 Universiy Blvd, Vancouver, BC V6T1Z3, Canada
AU: Hepburn, J W
EM: hepburn@chem.ubc.ca
AF: University of British Columbia, Chemistry Department 6174 Universiy Blvd, Vancouver, BC V6T1Z3, Canada
AU: Bertram, A K
EM: bertram@chem.ubc.ca
AF: University of British Columbia, Chemistry Department 6174 Universiy Blvd, Vancouver, BC V6T1Z3, Canada
AB: While state of the art aerosol mass spectrometers have dramatically expanded our knowledge of atmospheric aerosol composition and chemistry over the last decade, the analysis of complex organic mixtures still remains a challenge. We have developed a single particle mass spectrometer that combines a series of previously tried, promising approaches into one single instrument. Soft desorption (by using a dedicated pulsed CO2 laser, as shown by Prather, Baer & coworkers) and soft ionization (pulsed two photon UV ionization, as demonstrated by Prather, Zelenyuk, Zimmerman & coworkers) or tunable one photon VUV lasers (Baer, Leone & coworkers) to ensure a minimum of fragmentation. By ionizing the aerosol plume in the center of an ion trap both high sensitivity and the ability to elucidate structure by MS/MS (Reilly & coworkers) can be achieved. Coupled with a highly efficient aerosol focusing and timing interface (> 80% efficiency, < 2% timing precision, based on Prather & coworkers), this instrument shows promise to help elucidate the composition of accumulation mode organic particles for compounds up to 1500 Da Since "soft" methods, both in the desorption and ionization case are prone to massive biases, extensive testing has been done on examining the linear response of both for an array of aerosol sizes, test molecules, matrices and mixtures. In order to separate the effects of each step, desorption was studied using mixtures of PAHs that were ionized by two-photon UV, a well characterized and very sensitive ionization step.
DE: 0300 ATMOSPHERIC COMPOSITION AND STRUCTURE
DE: 0305 Aerosols and particles (0345, 4801, 4906)
DE: 0394 Instruments and techniques
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting