AAAR 34th Annual Conference
October 12 - October 16, 2015
Hyatt Regency
Minneapolis, Minnesota, USA
Abstract View
The Use of Pneumatic Nebulization to Enable Aerosol Based Measurements of 5-50 nm Particles in Liquid Suspensions
SEONGHO JEON, Gary Van Schooneveld, Derek Oberreit, Christopher Hogan Jr., University of Minnesota
Abstract Number: 80 Working Group: Instrumentation and Methods
Abstract Size distribution measurement is not only important in aerosol science, but is also critical for nanomaterials synthesized or dispersed in liquids. Unfortunately, existing liquid phase analytical techniques (namely, photon correlation spectroscopy) are problematic to apply to multimodal distributions of particles and additionally, do not readily yield nanoparticle number concentrations. Conversely, for aerosol particles, scanning mobility particle spectrometers (SMPSs) can facilitate the measurement of multimodal distributions and with proper size distribution inversion, they enable better estimate of nanoparticle concentrations. While electrosprays have been used previously to aerosolize nanomaterials, enabling SMPS measurements, the suspension conductivity and chemical composition requirements for electrosprays are extremely restrictive, and are hence not appropriate for a number of nanomaterials (i.e. those suspended in high non-volatile salt concentration environments). In this work, we apply a newly developed pneumatic nebulization system with online high-purity water dilution to aerosolize nanomaterials with diameters as small as 5 nm, and show that with this technique it is possible to make SMPS measurements of a variety of nanoparticles. Results are specifically shown for gold and silver particles and particle mixtures, proteins, particles in phosphate buffered saline, and gold nanorods. In all situations, minimal solution preparation is needed. Importantly we show that with fixed nebulization conditions, SMPS inferred size distribution functions can be used to yield a size, material, and suspension composition independent calibration curve to directly determine concentrations (with a dynamic range of five orders of magnitidue) in the liquid phase. Overall, this work demonstrates the potential of aerosol technology for quantitative measurements of nanomaterial suspensions.