Evaluating the Utility of an Atmospheric Pressure Chemical Ionization Mass Spectrometer for Analyzing Organic Peroxides

Speaker: Amanda Jameer  
Description: Secondary organic aerosols (SOA) are known to affect the earth’s radiation budget through its ability to scatter and absorb radiation. Consequently, the mechanisms and factors that influence SOA composition and formation are poorly understood. However, recent modeling studies coupled with smog chamber experiments suggest that organic peroxides (organic hydroperoxides and peroxyhemiacetals) might be a major component of SOA composition under low NO_x conditions. This study utilized an atmospheric pressure chemical ionization mass spectrometer (APCI-MS) in the positive mode to detect organic peroxides.

Mass spectra of organic peroxides analyzed in this study show excessive fragmentation during ionization with protonated water clusters. It was believed that intact ions were not found due to decomposition in the ion source. However, stable adduct ions were observed when methanol was used as an ionization reagent. Results comparing ionization with protonated water and methanol will be presented.