Electrospray Differential Mobility Hyphenated with Single Particle Mass Spectrometry for Characterization of Nanoparticles and their Aggregates
Jiaojie Tan, Jingyu Liu, Mingdong M. Li, Hind El Hadri, Vincent A. Hackley, Michael R. Zachariah
The hyphenation of electrospray-differential mobility analysis with single particle-inductively coupled plasma mass spectrometry (ES-DMA-spICP-MS) 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 mobility size discrimination with high resolution by controlling an applied voltage in step mode. Coupled by a gas exchange column, the downstream spICP-MS, 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 a NIST gold NP reference material. A detection limit of 〖10〗^5 mL-1 (NPs/mL) was determined, which is about four 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 NP aggregation states. Two demonstrative applications include gold NP mixtures with a broad size range (30 nm to 100 nm), and aggregated NPs with a primary size of 40 nm. Overall, we demonstrate the capacity of this new hyphenated technique 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 ICP-MS intensity (197Au in the present 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 spICP-MS mass.
, Liu, J.
, Li, M.
, El, H.
, Hackley, V.
and Zachariah, M.
Electrospray Differential Mobility Hyphenated with Single Particle Mass Spectrometry for Characterization of Nanoparticles and their Aggregates, Analytical Chemistry, [online], https://doi.org/10.1021/acs.analchem.6b01544
(Accessed December 4, 2023)