AAAR 35th Annual Conference October 17 - October 21, 2016 Oregon Convention Center Portland, Oregon, USA
Abstract View
Single Nanoparticle Characterization with a Laser Induced Plasma
ANDREW J. HORAN, Justin Krasnomowitz, Murray Johnston, University of Delaware
Abstract Number: 508 Working Group: Single Aerosol Particle Studies - Techniques and Instrumentation
Abstract Online determination of the chemical composition of nanoparticles poses a significant measurement challenge. The size and heterogeneity of individual nanoparticles in environmental samples require a technique which is both sensitive and robust across compositions. To this end, in both the laboratory and field, a laser induced plasma has been used to determine the elemental composition of individual nanoparticles with the Nano Aerosol Mass Spectrometer (NAMS). The laser radiation quantitatively converts the nanoparticle into multiply charged, positive, atomic ions, whose relative intensities yield the elemental composition. Most applications of this method have involved quantification of low atomic number non-metals (C, O, N, S, Si) in particles that are a few tens of nanometers in diameter. We have recently extended the technique to particles up to 100 nm and above, and we have characterized its ability to detect and quantify elements over a broader range of elements across the periodic table. Particle size and composition dependencies give insight into the mechanism of vaporization and ionization. For example, the ability to quantify metals in nanoparticles can be predicted using melting point as a proxy. Applications to a variety of particle types will be presented along with comparisons to more conventional analytical techniques.