Determination of Particle Vapor Pressures Using the Tandem Differential Mobility Analyzer

The application of the tandem differential mobility analyzer (TDMA) as a means of measuring vapor pressures of aerosol species is extended to include vapor saturation effects in the particle evaporator. To verify the analysis experiments were conducted with the controlled evaporation of dioctyl phthalate (DOP) particles with initial sizes ranging from 60 to 95 nm in diameter in a laminar flow evaporator. Vapor pressures of DOP determined with the TDMA were found to agree within 14% of those available in the literature. The results presented enable the use of the TDMA as a means to determine particle vapor pressure for substantially higher particle number concentrations than previously reported.