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Quantification of nanoparticle concentration in colloidal suspensions by a non-destructive optical method
Sandhya Clement1, Brint Gardner1,2, Wan Aizuddin W Razali3
1ARC Centre of Excellence for Nanoscale Biophotonics, Macquarie University, Sydney, NSW, Australia.
Nanotechnology
|September 20, 2017
Summary
This study introduces a rapid, non-destructive method using optical extinction and dynamic light scattering (DLS) to estimate nanoparticle number concentration. The technique accurately determines particle size distribution and concentration for various colloidal suspensions.
Area of Science:
- Colloidal science
- Nanomaterial characterization
- Optical physics
Background:
- Accurate nanoparticle number concentration is crucial for multi-stage reactions and nanomaterial applications.
- Existing methods for determining nanoparticle concentration can be destructive or lack precision.
- Characterizing particle size distribution (PSD) is essential for understanding colloidal suspension behavior.
Purpose of the Study:
- To develop a rapid, non-destructive method for estimating nanoparticle number concentration in colloidal suspensions.
- To combine optical extinction and dynamic light scattering (DLS) measurements with a numerical algorithm.
- To accurately determine both particle size distribution (PSD) and absolute concentration.
Main Methods:
- Utilizing Mie theory applied to optical extinction spectra of non-absorbing nanoparticles.
- Integrating measurements from common bench-top instrumentation.
- Employing a numerical algorithm to calculate PSD and concentration, accounting for DLS limitations.
Main Results:
- The method successfully estimates absolute particle number concentration for mono-, bi-modal, and broad PSDs.
- Achieved precision of less than 50% for nanoparticle number concentration estimation.
- Demonstrated a practical approach for determining concentration in colloidal nanomaterial applications.
Conclusions:
- The combined optical extinction and DLS method offers a convenient and practical solution for nanoparticle number concentration estimation.
- This technique is valuable for applications requiring precise quantification of colloidal nanomaterials.
- The approach addresses limitations in current PSD analysis from DLS for accurate concentration determination.
