Chemical ionization tandem mass spectrometer for the in situ measurement of methyl hydrogen peroxide.
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.
St Clair
Jason M
JM
Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California 91125, USA.
McCabe
David C
DC
Crounse
John D
JD
Steiner
Urs
U
Wennberg
Paul O
PO