Aerosol Spectrometer for On-Line Measuring Diameters and Chemical Compositions of Volatile Organic Nanoparticles

摘要

We describe the design and performance of an aerosol spectrometer that simultaneously measures size-dependent concentration and chemical composition of volatile organic nanoparticles ranging from 10 to 470 nm. The spectrometer consists of a differential mobility analyzer (DMA) for size classification and a gas chromatography mass spectrometer (GC-MS) for composition analysis. The size-classified particles of two kinds of hydrocarbons, an aliphatic hydrocarbon and aromatic hydrocarbon, were directly introduced into the GC-MS after vaporization of the particles. The relationships between the concentrations of classified particles measured with an aerosol electrometer and the peak area of major fragment ions measured with the GC-MS were given to show the detection limit of our spectrometer. For a particle size of 330 nm, the lower detection limit of the spectrometer for particle concentration was approximately 7.5×10(4) particles cm-3.