Tropospheric Chemistry: Instruments

I- ToF CIMS instrument

I- ToF CIMS instrument installed for airborne sampling

Iodide Ion ToF (Time-of-Flight) CIMS (Chemical Ionization Mass Spectrometer)

Principle of the Measurement

Chemical ionization mass spectrometric detection of gas phase organic and inorganic analytes via I- adduct formation

Species Measured

Reactive nitrogen species: HNO3 (nitric acid), HONO (nitrous acid), HO2NO2 (peroxynitric acid), N2O5 (dinitrogen pentoxide), HNCO (isocyanic acid)
Halogen Species: ClNO2, HCl, HBr, HOBr, HOCl, Cl2, Br2
Low to intermediate volatility organic species

Time Response

Instrumental response <1 sec, Field response is limited by inlet surface affinity for a particular species

Detection Limit

Precision on 1s data various by species

Accuracy

(15% + 1 pptv) for N2O5
(20% + 1 pptv) for ClNO2
(30% + 15 pptv) for HONO
(25% + 10 pptv) for HO2NO2
(15% + 15 pptv) for HNO3
(20% + 5 pptv) for HNCO
(20% + 15 pptv) for HCOOH
(30% + 1 pptv) for halogenated species

Manufacturer

TOFWERK/Aerodyne Research Inc. (modified)

Field Projects

  • ATom-3 Fall 2017
  • ATom-4 Spring 2018

Contacts

Patrick Veres, Andy Neuman

Key Publications

Veres, P. R., Roberts, J. M., Wild, R. J., Edwards, P. M., Brown, S. S., Bates, T. S., Quinn, P. K., Johnson, J. E., Zamora, R. J., and de Gouw, J., Peroxynitric acid (HO2NO2) measurements during the UBWOS 2013 and 2014 studies using iodide ion chemical ionization mass spectrometry, Atmos. Chem. Phys., doi:10.5194/acp-15-8101-2015, 2015.

Neuman, J. A., J. B. Nowak, L. G. Huey, J . B. Burkholder, J. E. Dibb, J. S. Holloway, J. Liao, J. Peischl, J. M. Roberts, T. B. Ryerson, E. Scheuer, H. Stark, R. E. Stickel, D. J. Tanner, and A. Weinheimer, Bromine measurements in ozone depleted air over the Arctic Ocean, Atmos. Chem. Phys., doi:10.5194/acp-10-6503-2010, 2010.

Neuman, J. A., T. B. Ryerson, L. G. Huey, R. Jakoubek, J. B. Nowak, C. Simons, and F. C. Fehsenfeld, Calibration and evaluation of nitric acid and ammonia permeation tubes by UV optical absorption, Environ. Sci. Technol., doi:10.1021/ES06422L, 2003.

Neuman, J. A., L. G. Huey, R. W. Dissly, F. C. Fehsenfeld, F. Flocke, J. C. Holecek, J. S. Holloway, G. Hübler, R. Jakoubek, D. K. Nicks Jr., D. D. Parrish, T.B. Ryerson, D. T. Sueper, and A. J. Weinheimer, Fast-response airborne in situ measurements of HNO3 during the Texas 2000 Air Quality Study, J. Geophys. Res., doi:10.1029/2001JD001437, 2002.