By Ebatco
Measuring the size of particles in suspended liquids or in dry powder format can be accomplished using particle size analysis based on the light scattering technique. Light refracted by a particle creates a scattering angle unique to its shape and size. The intensity of the scattering light is measured by an array of light detectors at different angles. The Mie Theory is the preferred method used to relate the measured scattering angle to the particle diameter. The Mie theory takes the complex refractive index of the particle into account when measuring the particle size. Nonetheless, in applications involving particles with high light absorption or with sizes significantly larger than the laser wavelength, the Fraunhofer Theory can be used to measure particle size. The Fraunhofer Theory is a simplified form of the Mie Theory; relating the scattering angle to the diameter of the particle and the light wavelength using the following equation: where θ is the measured scattering angle, λ is the wavelength of the laser light and d is the diameter of the particle. The complex refractive index of the particle required for the Mie Theory is not needed for the Fraunhofer Theory. The light scattering technique has been readily applied to measure particle size and size distribution of particles with sizes ranging from 18nm to 2000µm. Instrument: Beckman Coulter LS 13 320 Laser Diffraction Particle Size Analyzer with ULM and Sonication Control Unit connected Instrument Key Specifications - Particle Size Analysis Range 0.017-2000µm - Modules: Universal Liquid Module (ULM); Tornado Dry Powder System (Tornado DPS) - Analysis Theories: Fraunhofer; Mie - ULM Sample Requirements: Enough for 6-8% obscuration (40% with PIDS) - Tornado DPS Sample Requirements: 10-30mL or enough for 10 seconds run time Applications: Coffee Grounds, Complex Refractive Index, Dry Powder, Effect of Additives, Elastic Light Scattering, Extendable Size Detection Range, Fourier Lens, Fraunhofer Method, Liquid Suspension, Mie Theory, Mixture Purity, Motor Oils, Organic Mixtures, Particle Content, Particle Sizing, Particle Surfactants, Polarization Intensity Diffraction Scattering, Single Wavelength Detection, Soil, Tornado DPS, Universal Liquid Module
