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Beckmann Coulter LS 13 320 Particle size analyser with Universal Liquid module

The LS 13 320 by Beckman Coulter measures the particle size and the particle size distribution of a sample using light scattering. For bigger particles, the Frauenhofer theory on light scattering is being applied (further information at HELOS/KR). The Polarization Intensity Differential Scattering (PIDS) technology by Beckman Coulter enables the machine to analyse particles that are significantly smaller than the wavelength of visible light.

Facts List

Measured Parameter

Particle size, particle size distri-bution

Detection Method

Light scattering
PIDS

Range

0.017 μm to 2000 μm

Application

Particle size measurement

Materials

Emulsions e.g., lotions and creams
Dispersions e.g., paints and PCD

During a PIDS measurement, the sample is being irradiated with polarised light. If the particle size is significantly smaller than the wavelength of the irradiated light, the particle’s electrons are excited by the oscillating electric field of the light. The electrons oscillate perpendicular to the light beam and gen-erate therefore an oscillating dipole moment, which in turn radiates light in all directions except in the direction of its oscillating movement. The measured signal intensity from the sample differs depending on the angle. These values are strongly related to the ratio of particle size and wavelength. PIDS measurements are usually conducted at several differing wavelengths. This leads to data on particle size distribution as well as more refined results.

Beckman Coulter

© 2018 Beckman Coulter, Inc.

Backman Coulter - Schematic representation of the structure

Construction of the particle size analyser with the PIDS detector in the upper part and the light scattering detector in the lower part.
© 2011 Beckman Coulter, Inc.

PSD measurement of a skin protection cream using Beckman Coulter

PIDS measurement of a skin protection cream with Beckman Coulter’s LS 13 320.
© 2021 HSLU-T&A (Analytics lab)