How do Particle Size Analyzers work?
Laser diffraction analyzers pass a laser beam through a dispersed sample; particles scatter light at angles inversely related to their size, and a detector array records the angular intensity pattern. The Mie or Fraunhofer model converts this pattern into a volume-based size distribution. Dynamic light scattering instead measures intensity fluctuations caused by Brownian motion, and the Stokes–Einstein equation converts the diffusion coefficient into a hydrodynamic diameter. Dynamic image analysis captures particle silhouettes with a high-speed camera and reports size and shape descriptors directly. Sedimentation methods apply Stokes' law to settling velocity under gravity or centrifugal force. Key components include the light source, sample dispersion unit (wet or dry), detector array or correlator, and software with optical-property databases.
Which Particle Size Analyzers variants are available?
- Wet-Dispersion Laser Diffraction Particle Size Analyzer — A laser diffraction analyzer with a recirculating wet dispersion unit, stirring and ultrasonic deagglomeration.
- Dry-Powder Laser Diffraction Particle Size Analyzer — A laser diffraction analyzer that disperses powders in a compressed-air stream without liquid.
- Dynamic Light Scattering Particle Size Analyzer — A dynamic light scattering analyzer that determines hydrodynamic diameter of sub-micron particles and macromolecules from Brownian-motion fluctuations.
- Dynamic Image Particle Size and Shape Analyzer — An image-based analyzer that films particles in free fall or flow with high-speed cameras and reports size together with shape parameters such as aspect ratio and circularity.
- Centrifugal Sedimentation Particle Size Analyzer — A sedimentation analyzer that applies Stokes' law under centrifugal force, detecting particles by light or X-ray attenuation as they settle.
How do I choose the right variant?
Start from the expected size range and sample state. Laser diffraction covers roughly 0.1 to 3500 µm and suits most powders and suspensions; dynamic light scattering is preferred below about 1 µm; dynamic image analysis is chosen when shape matters or when a few oversize particles must be detected; centrifugal sedimentation resolves narrow multimodal distributions of fine particles. Next decide between wet and dry dispersion: dry dispersion avoids solvents and suits free-flowing powders, while wet dispersion gives better deagglomeration of cohesive or fine materials. Check whether the method must follow ISO 13320 or USP <429>, and whether 21 CFR Part 11 audit trails are needed. Also consider sample volume, automation, cleaning time between samples and the availability of validated SOP templates.
Where are Particle Size Analyzers used?
Particle Size Analyzers are specified in pharmaceutical powder and inhaler development, battery cathode and anode materials, ceramics and cement, pigments, paints and coatings, food and dairy emulsions and mining and mineral processing.
Which standards and certifications apply?
Work with Particle Size Analyzers is commonly governed by ISO 13320, USP <429>, ISO 13322-1, ISO 13322-2, ISO 22412, GB/T 19077 and Ph. Eur. 2.9.31. Instrument certifications such as CE marking are confirmed per configuration and never assumed.
What are the key considerations before purchase?
Particle size results depend heavily on sampling and dispersion, so representative sub-sampling, a documented dispersion protocol and sonication or pressure settings must be validated for each material. Install the instrument on a vibration-free bench away from direct sunlight, and keep the optical bench clean; check background and alignment before each session. Verify performance periodically with certified reference materials such as polystyrene latex or glass beads, following ISO 13320 acceptance criteria. Replace dispersant and clean the cell to avoid carry-over. Enter refractive index and absorption values correctly, because they strongly influence Mie results. Regulated laboratories should perform IQ/OQ/PQ and use audit-trail-enabled software.
