"Depth-Profiling" and Quantitative Characterization of the Size, Composition, Shape, Density, and Morphology of Fine Particles with SPLAT, a Single-Particle Mass Spectrometer

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• 作者：Alla Zelenyuk ; Juan Yang ; Chen Song ; Rahul A. Zaveri ; Dan Imre
• 刊名：Journal of Physical Chemistry A
• 出版年：2008
• 出版时间：January 31, 2008
• 年：2008
• 卷：112
• 期：4
• 页码：669 - 677
• 全文大小：289K
• 年卷期：v.112,no.4(January 31, 2008)
• ISSN：1520-5215

文摘

A significant fraction of atmospheric particles are composed of inorganic substances that are mixed or coatedwith organic compounds. The properties and behavior of these particles depend on the internal compositionand arrangement of the specific constituents in each particle. It is important to know which constituent is onthe surface and whether it covers the particle surface partially or entirely. We demonstrate here an instrumentconsisting of an ultrasensitive single-particle mass spectrometer coupled with a differential mobility analyzerto quantitatively measure in real time individual particle composition, size, density, and shape and to determinewhich substance is on the surface and whether it entirely covers the particle. For this study, we use NaClparticles completely coated with liquid dioctyl phthalate to generate spherical particles, and NaCl particlespartially coated with pyrene, a solid poly aromatic hydrocarbon, to produce aspherical particles with pyrenenodules and an exposed NaCl core. We show that the behavior of the mass spectral intensities as a functionof laser fluence yields information that can be used to determine the morphological distribution of individualparticle constituents.