Size-resolved online chemical analysis of nanoaerosol particles: a thermal desorption differential mobility analyzer coupled to a chemical ionization time-of-flight mass spectrometer
oleh: A. C. Wagner, A. Bergen, S. Brilke, S. Brilke, C. Fuchs, C. Fuchs, M. Ernst, J. Hoker, M. Heinritzi, M. Simon, B. Bühner, J. Curtius, A. Kürten
| Format: | Article |
|---|---|
| Diterbitkan: | Copernicus Publications 2018-10-01 |
Deskripsi
<p>A new method for size-resolved chemical analysis of nucleation mode aerosol particles (size range from ∼ 10 to ∼ 30 nm) is presented. The Thermal Desorption Differential Mobility Analyzer (TD-DMA) uses an online, discontinuous principle. The particles are charged, a specific size is selected by differential mobility analysis and they are collected on a filament by electrostatic precipitation. Subsequently, the sampled mass is evaporated in a clean carrier gas and analyzed by a chemical ionization mass spectrometer. Gas-phase measurements are performed with the same mass spectrometer during the sampling of particles. The characterization shows reproducible results, with a particle size resolution of 1.19 and the transmission efficiency for 15 nm particles being slightly above 50 %. The signal from the evaporation of a test substance can be detected starting from 0.01 ng and shows a linear response in the mass spectrometer. Instrument operation in the range of pg m<sup>−3</sup> is demonstrated by an example measurement of 15 nm particles produced by nucleation from dimethylamine, sulfuric acid and water.</p>