AAAR 34th Annual Conference
October 12 - October 16, 2015
Hyatt Regency
Minneapolis, Minnesota, USA
Abstract View
Electrospray-Differential Mobility Hyphenated with Single Particle-Inductively Coupled Plasma Mass Spectrometry for Characterization of Nanoparticles and Their Aggregates
JIAOJIE TAN, Jingyu Liu, Mingdong Li, Hind El Hadri, Vincent Hackley, Michael Zachariah, National Institute of Standards and Technology
Abstract Number: 195 Working Group: Instrumentation and Methods
Abstract The hyphenation of electrospray-differential mobility analysis with single particle-inductively coupled plasma mass spectrometry (ES-DMA-spICPMS) was demonstrated with the capacity for real-time size, mass and concentration measurement of nanoparticles (NPs) on a particle-to-particle basis. The ES delivers an aerosolized sample to a customized DMA system, which achieves size discrimination with high resolution by controlling the applied voltage in step mode. Coupled by a gas exchange column, the downstream spICPMS, operates in time-resolved mode and detects element-specific NP mass as single particle events.
In this proof-of-principle study, the feasibility of this technique was validated through both concentration and mass calibration using NIST reference gold NPs. A detection limit of 10$^7 NPs/mL was determined, which is about two orders of magnitude lower in comparison to a traditional ES-DMA setup using a condensation particle counter as the principal detector. Furthermore, independent and simultaneous quantification of both size and mass of NPs provides information regarding nanoparticle aggregation states. Two demonstrative applications include gold NP mixtures with a broad size range (30nm to 100nm), and aggregated NPs with a primary size of 40 nm.
Overall, this new hyphenated technique demonstrated the capacity for: 1) Clearly resolving nanoparticle populations from a mixture containing a broad size range; 2) Defining a linear relationship between mobility size and one-third power of intensity (Au$^197 in our case) for spherical NPs; 3) Monitoring propagation of NP aggregation with well characterized oligomers; and 4) Differentiating aggregated NPs and non-aggregated states based on the “apparent density” derived from both DMA size and spICPMS mass.