Tropospheric Chemistry: VOC Instruments

Gas Chromatography - Mass Spectrometry (GC-MS)

GC-MS instrument
ACCBAR GC-MS instrument

iWAS instrument
iWAS canisters and analysis rack

Principle of the Measurement

The NOAA GC-MS, also referred to as ACCBAR (Advanced Cryo-mechanical Chromatograph for Biospheric-Atmospheric Research), is a custom-built, two-channel gas chromatograph coupled to a quadrupole mass spectrometer detector (Agilent 5975C). The instrument is capable of collecting in-situ samples for immediate analysis or for automated analysis of the integrated whole air samplers (iWAS). Additionally, the GC front end can be coupled to the NOAA PTR-ToF-MS for identification of isobaric species and mass fragments. The GC-MS utilizes a series of traps to reduce carbon dioxide, ozone, and water prior to preconcentrating volatile organic compounds (VOCs) at liquid nitrogen temperatures via a Stirling Cooler (CryoTel GT by Sunpower Inc.).

Species Measured

C2-C11 hydrocarbons, C1-C8 oxygenated volatile organic compounds, C1-C7 volatiles nitrogen (e.g., nitriles and alkyl nitrates), and other sulfur and halogenated volatiles

Time Response / Detection Limit

Collects a 4-minute sample to preconcentrate VOCs prior to analysis. Total duty cycle is 20 minutes per sample. Detection limits are compound dependent but generally range in the 1-10 parts-per-trillion (ppt).

Manufacturer

Custom built instrument utilizing commercial components

Field Projects

Contacts

Jessica Gilman, Aaron Lamplugh

Key Publications

Lerner, B.M., J.B. Gilman, K.C. Aikin, E.L. Atlas, P.D. Goldan, M. Graus, R. Hendershot, G.A. Isaacman-VanWertz, A. Koss, W.C. Kuster, R.A. Lueb, R.J. McLaughlin, J. Peischl, D. Sueper, T.B. Ryerson, T.W. Tokarek, C. Warneke, B. Yuan, and J.A. de Gouw, An improved, automated whole-air sampler and gas chromatography mass spectrometry analysis system for volatile organic compounds in the atmosphere, Atmospheric Measurement Techniques, doi:10.5194/amt-10-291-2017, 2017.

Koss, A.R., K. Sekimoto, J.B. Gilman, V. Selimovic, M.M. Coggon, K.J. Zarzana, B. Yuan, B.M. Lerner, S.S. Brown, J.-L. Jimenez, J. Krechmer, J.M. Roberts, C. Warneke, R.J. Yokelson, and J. de Gouw, Non-methane organic gas emissions from biomass burning: identification, quantification, and emission factors from PTR-ToF during the FIREX 2016 laboratory experiment, Atmospheric Chemistry and Physics, doi:10.5194/acp-18-3299-2018, 2018.