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Published September 2010 | Published
Journal Article Open

Chemical ionization tandem mass spectrometer for the in situ measurement of methyl hydrogen peroxide

Abstract

A new approach for measuring gas-phase methyl hydrogen peroxide [(MHP) CH_3OOH] utilizing chemical ionization mass spectrometry is presented. Tandem mass spectrometry is used to avoid mass interferences that hindered previous attempts to measure atmospheric CH_3OOH with CF_3O− clustering chemistry. CH_3OOH has been successfully measured in situ using this technique during both airborne and ground-based campaigns. The accuracy and precision for the MHP measurement are a function of water vapor mixing ratio. Typical precision at 500 pptv MHP and 100 ppmv H_2O is ±80 pptv (2 sigma) for a 1 s integration period. The accuracy at 100 ppmv H_2O is estimated to be better than ±40%. Chemical ionization tandem mass spectrometry shows considerable promise for the determination of in situ atmospheric trace gas mixing ratios where isobaric compounds or mass interferences impede accurate measurements.

Additional Information

© 2010 American Institute of Physics. Received 6 April 2010; accepted 27 July 2010; published online 22 September 2010. We thank James Oliver for support with mechanical designs used for the fabrication of custom parts in this instrument as well as parts needed for integration onto the aircraft and Norton Allen for support with the QNX-based control/ data-collection software. We also thank NCAR/NSF C-130 and NASA DC-8 aircraft crew, pilots, and engineers and support staff for assistance with integration of instrumentation onto aircraft and for successful completion of science missions. Funding for this research was provided by the NASA Tropospheric Chemistry Program. This instrument would have not been possible without the financial support of Caltech trustee William Davidow. J.D.C. acknowledges EPA-STAR Fellowship Program (Contract No. FP916334012) support. This work has not been formally reviewed by the EPA. The views expressed in this document are solely those of the authors and the EPA does not endorse any products or commercial services mentioned in this publication.

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Published - StClair2010p11618Review_of_Scientific_Instruments.pdf

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Additional details

Created:
August 22, 2023
Modified:
October 20, 2023