Accurate Sizing of Nanoparticles Using a High-Throughput Charge Detection Mass Spectrometer without Energy Selection.
Conner C Harper1, Zachary M Miller1, Matthew S McPartlan1
1Department of Chemistry, University of California, Berkeley, California 94720-1460, United States.
ACS Nano
|April 7, 2023
Summary
Charge detection mass spectrometry (CDMS) offers a faster and more accurate way to measure nanoparticle sizes. This advanced technique analyzes individual particles, revealing details like dimerization in solution missed by traditional methods.
Area of Science:
- Nanotechnology
- Analytical Chemistry
- Materials Science
Background:
- Nanoparticle size and shape critically influence chemical and material properties.
- Existing sizing methods (light scattering, mobility, microscopy) have limitations in specificity, sample preparation, and analysis time.
- Individual particle characterization is crucial for understanding nanoparticle behavior.
Purpose of the Study:
- To describe a newly constructed, high-speed, accurate charge detection mass spectrometry (CDMS) instrument for nanoparticle characterization.
- To evaluate the performance of CDMS for nanoparticle sizing compared to transmission electron microscopy (TEM).
- To demonstrate the capability of CDMS to detect nanoparticle aggregation in solution.
Main Methods:
- Characterization of polystyrene nanoparticles (∼100 nm and ∼50 nm amine-functionalized) using CDMS and TEM.
- Direct, in situ measurement of individual ion masses by CDMS without relying on ion energy filters.
- Transformation of CDMS-measured masses to particle diameters for size distribution analysis.
Main Results:
- CDMS-derived nanoparticle size distributions closely matched those obtained by TEM.
- CDMS detected nanoparticle dimerization in solution, an observation not possible with TEM due to sample drying artifacts.
- CDMS demonstrated significantly faster particle sizing rates (up to 80×) compared to TEM, even with more dilute samples.
Conclusions:
- The developed CDMS instrument provides accurate, individual nanoparticle measurements with high throughput.
- CDMS offers a superior alternative to conventional methods for rapid and detailed nanoparticle size analysis.
- This advancement in CDMS technology enhances capabilities for understanding nanoparticle properties and behavior in various applications.
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