Dynamic Light Scattering Particle Size Analyzer How It Works and When to Use It

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Understanding the size and distribution of nanoparticles is essential across research and manufacturing. From pharmaceuticals and cosmetics to semiconductors and nanomaterials, particle size directly affects performance, stability, and quality.

One of the most widely used and trusted techniques for this purpose is Dynamic Light Scattering (DLS). A DLS particle size analyzer offers a fast, non-destructive, and precise way to measure particles in the nanometer to micrometer range.

In this post, we’ll explain how DLS works, when it’s the right method to use, and how advanced instruments from Cordouan Technologies available through Barnett Technical Services take DLS measurement to the next level.

What Is Dynamic Light Scattering (DLS)?

Dynamic Light Scattering (DLS) is a light scattering technique that measures the Brownian motion of particles suspended in a liquid. When a laser beam passes through a particle suspension, light scatters in all directions. Because particles undergo random thermal motion (Brownian motion), the intensity of scattered light fluctuates over time. Smaller particles move faster and create more rapid fluctuations; larger particles move slower with slower fluctuations.

By analyzing these time-dependent intensity fluctuations using autocorrelation functions and sophisticated algorithms, a DLS analyzer determines the diffusion coefficient of the particles. This is then converted into hydrodynamic diameter using the Stokes-Einstein equationproviding a measurement of particle size in its native liquid environment.

How a Dynamic Light Scattering Particle Size Analyzer Works

A typical DLS system consists of four key components:

1. Laser Light Source
   A stable laser provides the monochromatic light that interacts with the suspended particles.
2. Sample Cell
   The liquid sample containing nanoparticles is held in a cuvette or measurement cell. Some instruments, like Cordouan’s Vasco Kin, allow in situ measurement directly within the process stream.
3. Detector and Correlator
   The detector captures scattered light at a specific angle. The correlator analyzes the intensity fluctuations to calculate particle motion and, ultimately, particle size.
4. Data Processing Software
   Advanced algorithms convert the correlation data into a size distribution profile, showing the mean diameter, polydispersity index (PDI), and overall particle uniformity.

Advantages of DLS for Particle Size Measurement

• Fast and Non-Destructive – Results are available in minutes with no need to alter or destroy the sample.
• Broad Size Range – Measures particles typically between 1 nm and 10 µm, depending on concentration and sample type.
• High Sensitivity – Detects subtle changes in particle size due to aggregation, crystallization, or dissolution.
• Minimal Sample Volume – Only a small amount of sample is required, ideal for expensive formulations.
• Repeatable and Reliable – Automated analysis minimizes operator error.

When to Use DLS

DLS is ideal for systems where particles are spherical or near-spherical and suspended in a homogeneous liquid medium. It’s commonly used in:

• Pharmaceuticals and Biopharma – Determining the size of liposomes, lipid nanoparticles, and protein aggregates.
• Nanomaterials and Colloids – Measuring nanofluids, metal oxides, and polymer dispersions.
• Chemical and Materials Science – Monitoring emulsions, suspensions, and crystallization processes.
• Cosmetics and Food Science – Evaluating emulsifier performance and product stability.

DLS is best for samples with relatively narrow size distributions and particles that do not sediment or interact strongly.

Cordouan Technologies: Precision DLS Instruments for Every Application

As a leader in light-scattering instrumentation, Cordouan Technologies offers a complete portfolio of DLS analyzers to suit different needs:

• Amerigo – All-in-One Analyzer: Combines particle size, zeta potential, and molecular weight measurements in a single instrument. Ideal for research laboratories requiring comprehensive nanoparticle characterization.
• Vasco Series – Versatile Particle Size Analysis: Delivers high-resolution DLS measurements for a wide range of samples, including dark or concentrated dispersions.
• Vasco Kin – In Situ Real-Time DLS: Provides real-time monitoring of particle size directly in the process, enabling dynamic studies and process control applications.

Each system features Cordouan’s advanced DLS algorithms, temperature control, and intuitive software interface- ensuring accuracy, reproducibility, and ease of use.

Choose the Right DLS Analyzer for Your Application

Whether you need high-precision lab measurements or real-time process monitoring, Barnett Technical Services can help you identify the best Cordouan analyzer for your research or production needs.

As an authorized distributor of Cordouan Technologies, Barnett provides expert consultation, demonstrations, and application support across North America.

Explore Cordouan’s DLS solutions today.
 Contact Barnett Technical Services to schedule a demo or request more information.