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In situ nanoparticle sizing with zeptomole sensitivity
Christopher Batchelor-McAuley1, Joanna Ellison, Kristina Tschulik
1Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, UK. richard.compton@chem.ox.ac.uk.
The Analyst
|June 9, 2015
Summary
A novel electrochemical method, nanoparticle coulometry, accurately sizes nanoparticles in situ. This technique detects zeptomole quantities of silver nanoparticles, offering a disruptive nano-technology for precise size distribution analysis.
Area of Science:
- Electrochemistry
- Nanotechnology
- Materials Science
Background:
- Accurate in situ nanoparticle sizing is crucial for various scientific and industrial applications.
- Current methods like TEM and optical tracking have limitations in sensitivity and scope.
- Developing novel electrochemical techniques offers potential for enhanced nanoparticle characterization.
Purpose of the Study:
- To introduce and validate a new electrochemical approach for in situ nanoparticle sizing.
- To demonstrate the capability of nanoparticle coulometry for detecting and sizing small quantities of nanoparticles.
- To compare the results of nanoparticle coulometry with established techniques like TEM.
Main Methods:
- Utilizing in situ particle coulometry to detect and measure stochastic charge transfer from individual nanoparticles.
- Quantifying nanoparticle size based on electron transfer measurements, correlating charge to volume.
- Analyzing the resulting particle size distribution and comparing it with Transmission Electron Microscopy (TEM) data.
Main Results:
- Successfully detected and sized silver nanoparticles containing as little as 12 zeptomoles (10^-21 moles).
- Coulometric measurements yielded direct information on individual nanoparticle volumes, with an average equivalent radius of 5 nm.
- Particle size distribution obtained via nanoparticle coulometry showed excellent agreement with TEM analysis.
- Demonstrated a measurable particle size limit significantly below common optical nanoparticle tracking techniques.
Conclusions:
- Nanoparticle coulometry provides a highly sensitive and accurate method for in situ nanoparticle sizing.
- This electrochemical technique offers a disruptive nano-technology with potential to surpass current optical methods.
- The method's ability to size nanoparticles at the zeptomole level opens new avenues in nano-characterization.
