Particle characterization
Particle Size Analysis (DLS and Laser Diffraction)
Particle-size analysis measures a distribution, but the correct technique depends on whether the sample is a nanoscale dispersion, micron-scale powder, suspension, or emulsion.
Dynamic Light Scattering estimates hydrodynamic size from Brownian motion in a liquid, while laser diffraction infers a broader particle-size distribution from angular light scattering. RNDgrid helps choose the method based on expected range, dispersibility, concentration, refractive information, and whether agglomerates should remain or be dispersed.
When this method is useful
- Nanoparticle dispersions, colloids, emulsions, pigments, powders, slurries, pharmaceuticals, and materials processing
- Size distribution, batch comparison, dispersion optimization, agglomeration, and formulation stability studies
- Projects comparing DLS with zeta potential or laser-diffraction micron PSA
What the report can include
- Size distribution using the instrument's stated basis and model
- DLS intensity distribution, cumulants, and polydispersity where applicable
- Laser-diffraction percentile values such as D10, D50, and D90 when applicable
Sample preparation and scoping
- Provide expected size range, medium, concentration, density or refractive information, and dispersion method.
- Remove dust and bubbles without selectively removing real particles.
- Define sonication, dispersant, surfactant, stirring, and agglomerate treatment before comparison.
Limitations to consider
- DLS is highly intensity-weighted and can be dominated by a small number of larger contaminants or agglomerates.
- Laser diffraction uses an optical model and may not distinguish shapes or multimodal populations unambiguously.
- Results from different techniques or preparation procedures are not automatically interchangeable.
Capabilities, detection limits, accreditation scope, and turnaround vary by method and partner laboratory. Confirm the final scope in the quotation before sending samples.
Questions to answer before booking
- Is the sample a stable liquid dispersion, emulsion, dry powder, or slurry?
- Is the expected range nanometres, micrometres, or broad/multimodal?
- Do you need hydrodynamic size, volume distribution, dry dispersion, or zeta potential too?
Related methods
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