Dynamic Light Scattering
Particle size distribution and polydispersity measurement in liquid suspensions.
O que é DLS
Uma técnica de análise avançada
Particle size distribution and polydispersity measurement in liquid suspensions.
What sets us apart
We don't hand over a spectrum. We hand over the interpretation.
Any lab can return peaks and numbers. Our report reads the data. Three differences define what we deliver — illustrated below with a real, anonymized case.
Multiple techniques, one integrated report
We don't hand back five loose reports. We cross-reference every technique's results into a single reading — each signal checked against the others — to reach an answer, not a pile of data.
- Contamination investigation — identifying and tracing the source of a foreign species.
- Performance degradation — explaining why a batch behaves outside expectations.
- New supplier validation — proving equivalence before switching.
3 LDPE batches · 4 techniques converge, NMR reveals the difference
In semicrystalline polymer systems, thermomechanical processing variables influence chain conformational dynamics¹. Solid-state NMR resolves chemical environments at the nanometer scale², sensitive to changes not detectable by XRD or FTIR³.
Technical justification anchored in the literature
Every technique choice and every inference in the report is backed by peer-reviewed literature — with citations in the text. The conclusion isn't loose opinion: it's a traceable argument, defensible in an audit and in front of the client.
- Numbered citations linking claim to source
- Official standards and methods referenced per analyte
- Auditable reasoning end to end
Conclusion and expert opinion
The report closes with a clear position, signed by the Principal Investigator: what the data shows, what can't yet be claimed, and the next step. It includes an honest caveat on the limits of inference — what separates a technical opinion from a guess.
- Explicit technical position, not just results
- Inference limits declared honestly
- Next-step recommendation signed by the P.I.
Four techniques confirmed equivalence; only the solid-state NMR revealed the subtle conformational change not distinguishable by conventional QC — a molecular signature consistent with the atypical filtration behavior.
Without the industrial line's parameters, no direct causal correlation can be established — a complementary step is recommended for elucidation.
Aplicações de mercado
Onde a DLS entrega resultados
Market Applications
Pharma
- Nanoparticle characterization
- Protein aggregation analysis
- Liposome quality control
- Stability monitoring
- Nanostructured system development
Materials
- Size distribution analysis
- Nanoparticle characterization
- Dispersion studies
- Suspension quality control
- Polydispersity analysis
Cosmetics
- Nanoemulsion characterization
- Droplet size analysis
- Product quality control
- Colloidal stability studies
- Delivery system development
FAQ
Frequently Asked Questions about Dynamic Light Scattering (DLS)
What are the limitations of DLS for polydisperse or multimodal samples?
- DLS reports an intensity-weighted average and is inherently biased toward larger particles, since scattering intensity scales with the sixth power of particle diameter — a small population of larger particles or aggregates can dominate the measured signal even if it represents a tiny fraction of the sample by number or volume. Samples with more than two or three distinct size populations, or a very broad size distribution, are harder for DLS to resolve accurately and may benefit from a complementary technique.
What sample concentration is needed for DLS?
- DLS requires enough particles in the light path to generate a measurable scattering signal, but not so many that multiple scattering (light bouncing off more than one particle before reaching the detector) distorts the result — the appropriate concentration and dilution are established for each sample type during method setup.
Can DLS distinguish between individual particles and aggregates?
- DLS reports an overall size distribution rather than imaging individual particles, so while it is highly sensitive to the presence of aggregates (which shift the average size and broaden the distribution), it cannot visually confirm aggregate morphology the way electron microscopy can — the two are often used together when aggregate identity, not just size, matters.
How does temperature affect a DLS measurement?
- Because DLS relies on the Brownian motion of particles, which is temperature-dependent, measurements are performed at a precisely controlled temperature; even small temperature fluctuations can shift the apparent particle size or destabilize a formulation during the measurement itself.
What is the polydispersity index (PDI) and what values are considered acceptable?
- The PDI is a dimensionless measure of the width of the particle size distribution, ranging from 0 (perfectly uniform) to 1 (highly polydisperse). A PDI below roughly 0.1-0.2 is generally considered monodisperse/narrow, while higher values indicate a broader or potentially multimodal distribution — acceptable thresholds depend on the specific formulation and its intended use.
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