Diluted and aged mainstream smoke aerosol particles have been analyzed using aerosol time of flight mass spectrometry. Two continuous wave (CW) lasers are being used for size determination and an UV laser having a wavelength of 266nm is being employed for ionization of species in the particles. Both positive and negative ion mass spectra have been acquired for the smoke aerosol particles using air as a dilution medium. An averaged positive ion mass spectrum shows peaks appearing at lower masses arising predominantly due to fragmentation from polycyclic aromatic hydrocarbons (PAHs). The negative ion mass spectra suggest that these ionic species largely disintegrate into carbon cluster fragments such as Cn - and CnH -. In addition, the negative ion mass spectra show a dominant CN - peak apart from N- and O-related species such as NO-, NO2 -, and NO3 -. A reaction mechanism in the case of aged smoke where oxidation of NO occurs followed by reaction with methanol forming methyl nitrite and nitric acid is supported by data where a large NO3 - signal is seen in the mass spectrum. The mass spectrum produced under reduced molecular ion fragmentation conditions show the presence of a large number of closely spaced peaks ranging from low molecular weights to high, for positive as well as negative ions.
- Polycyclic aromatic hydrocarbons
- Single particle mass spectrometry
ASJC Scopus subject areas
- Analytical Chemistry
- Fuel Technology