HR: 0800h
AN: A11B-0051    [Abstracts]
TI: Selective Mass Spectrometer Characterization of Halogen Gases in Air at Atmospheric Pressure
AU: * Dahl, S
EM: stdahl@hotmail.com
AF: California State University, Los Angeles, 5151 State University Drive, Los Angeles, CA 90032-8202
AU: Ivey, M M
EM: michelle_ivey@HMC.edu
AF: California State University, Los Angeles, 5151 State University Drive, Los Angeles, CA 90032-8202
AU: Foster, K L
EM: kfoster@calstatela.edu
AF: California State University, Los Angeles, 5151 State University Drive, Los Angeles, CA 90032-8202
AU: Foster, K L
EM: kfoster@calstatela.edu
AF: CEA-CREST Program, 5151 State University Drive, Los Angeles, CA 90032-8201
AB: We have developed a new interface for use with a commercial ion-trap mass spectrometer equipped with atmospheric pressure chemical ionization (APCI-MS). The new interface uses a mechanical pump to draw gaseous analyte through a glass manifold and into the corona discharge area of the APCI-MS. This new method of delivering a gaseous sample at atmospheric pressure directly to the MS has been used to obtain real-time measurements of Br$_{2}$ and Cl$_{2}$ over synthetic seawater ice. The ion intensity of a halogen gas measured by the MS is affected by the pumping rate and the position of the glass manifold. The MS signals for Br$_{2}$ are linear in the 0.1 to 10.6 ppbv range, and the estimated 3 sigma detection limit is 20.7 pptv. The MS signals for Cl$_{2}$ are linear in the 0.2 to 25 ppbv range, and the estimated 3 sigma detection limit is 1.081 ppbv. This lab-based technique is suitable to be the basis for a portable field-based design. Such a design, a miniaturized instrument, will help elucidate the role of seawater snow and ice surfaces on the photochemical production of Br$_{2}$ and Cl$_{2}$ in the high Arctic.
DE: 9315 Arctic region
DE: 4894 Instruments and techniques
DE: 0317 Chemical kinetic and photochemical properties
DE: 0365 Troposphere--composition and chemistry
DE: 0394 Instruments and techniques
SC: Atmospheric Sciences [A]
MN: 2004 AGU Fall Meeting