Laboratory Investigations of Aerosol Reactions Using Chemical Ionization Mass Spectrometry

The technique of chemical ionization mass spectrometry (CIMS) has been used for the direct, real-time analysis of aerosols in the study of gas-particle reactions. The use of multiple reagent ions, both positive and negative, allows detection of a wide range of particle constituents, including organic species, such as aldehydes, ketones, carboxylic acids, alcohols and alkanes, as well as halogenated molecules and nitrates. Thermal vaporization of the particles coupled with CIMS provides a relatively low degree of fragmentation of many condensed-phase organic species thereby enhancing identification and quantification. Recent results using this technique in laboratory studies of gas-particle reactions of atmospheric significance will be presented.