Aerosol Spectrometer for On-Liee 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. Foraparticlesizeof330nm, the lowerdetectionlimitofthespectrometerforparticle concentration was approximately 7.5 x 10~4 particles cm~(-3).