HR: 0800h
AN: A51B-0054    [Abstracts]
TI: Measurement of Atmospheric Isoprene Concentrations using an Automated Cylindrical Ion Trap Mass Spectrometer
AU: * Edwards, G D
EM: gdedward@purdue.edu
AF: Purdue University, Department of Chemistry, 560 Oval Drive, West Lafayette, IN 47907 United States
AU: Shepson, P B
EM: pshepson@purdue.edu
AF: Purdue University, Department of Chemistry, 560 Oval Drive, West Lafayette, IN 47907 United States
AU: Shepson, P B
EM: pshepson@purdue.edu
AF: Purdue University, Department of Earth and Atmospheric Science, 550 Stadium Mall Drive, West Lafayette, IN 47907 United States
AU: Grossenbacher, J W
EM: grossenbacher@griffinanalytical.com
AF: Griffin Analytical Technologies, 3000 Kent Avenue, West Lafayette, IN 47906 United States
AU: Wells, J M
EM: Wells@griffinanalytical.com
AF: Griffin Analytical Technologies, 3000 Kent Avenue, West Lafayette, IN 47906 United States
AU: Patterson, G
EM: Patterson@griffinanalytical.com
AF: Griffin Analytical Technologies, 3000 Kent Avenue, West Lafayette, IN 47906 United States
AU: Barkett, D J
EM: Barket@griffinanalytical.com
AF: Griffin Analytical Technologies, 3000 Kent Avenue, West Lafayette, IN 47906 United States
AB: Volatile organic compounds (VOCs) released from the biosphere have been shown to substantially influence both ozone and aerosol chemistry. However, field instruments for the detection of these trace gases are often limited by instrument portability and the ability to distinguish compounds of interest from background or other interfering compounds. We have developed an automated sampling system that is coupled to a lightweight, low power cylindrical ion trap mass spectrometer. This instrument was used for high frequency isoprene measurements at a recent field campaign at the University of Michigan Biological Station PROPHET lab. The inlet uses a sample loop and 6-port valves to trap ambient air samples without the aid of cryogens. VOCs are preconcentrated by sampling directly into a pre-cooled capillary column that is then heated by moving the column to a pre-heated region to obtain rapid separation of isoprene from other species. Isoprene eluting from the end of the column is then introduced to the mass spectrometer. The commercially available cylindrical ion trap (Minotaur 400) interfaced with our preconcentrator yields limits of detection of <80 ppt. The data obtained during the PROPHET 2005 campaign suggest the new inlet system, when coupled with the Minotaur 400 detector provides a feasible field instrument for the fast and accurate evaluation of trace gases over a variety of atmospheric conditions.
DE: 0365 Troposphere: composition and chemistry
DE: 0394 Instruments and techniques
DE: 0426 Biosphere/atmosphere interactions (0315)
SC: Atmospheric Sciences [A]
MN: Fall Meeting 2005