title: 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(3)OOH] utilizing chemical ionization mass spectrometry is presented. Tandem mass spectrometry is used to avoid mass interferences that hindered previous attempts to measure atmospheric CH(3)OOH with CF(3)O(-) clustering chemistry. CH(3)OOH 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(2)O is ±80 pptv (2 sigma) for a 1 s integration period. The accuracy at 100 ppmv H(2)O 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.
authors.affiliation: Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California 91125, USA.
authors.forename: Jason M
authors.initials: JM
authors.lastname: St Clair
authors.forename: David C
authors.initials: DC
authors.lastname: McCabe
authors.forename: John D
authors.initials: JD
authors.lastname: Crounse
authors.forename: Urs
authors.initials: U
authors.lastname: Steiner
authors.forename: Paul O
authors.initials: PO
authors.lastname: Wennberg