Physical Pharmacy 21 Particle Size Sizing Technique 3: Laser Diffraction Photon Correlation Spectroscopy Kausar Ahmad Kulliyyah of Pharmacy, IIUM

Physical Pharmacy 22 Light Scattering Reflected Diffracted Refracted When light strikes a particle, the light is then scattered in all direction.

Physical Pharmacy 23 Light scattered

Physical Pharmacy 24 Scattering Intensity

Physical Pharmacy 25 Static Light Scattering

Physical Pharmacy 26 Particle Sizing by Laser Diffraction

Physical Pharmacy 27 Mie Theory Application for particle size analysis

Physical Pharmacy 28 Laser Diffraction Configuration

Physical Pharmacy 29 Laser Diffraction Sizing Principle

Examples InstrumentLaser SourceDetectorLens Horiba LA-920He-Ne laser at nm for large particles, tungsten lamp at 405 nm for small particles. Ring detector array of 75 high- purity silicon elements Coulter LS100Consists of 126 Malvern Mastersizer E 2 mW He-Ne laser at nm 45 mm: 0.1 – 60  m 100 mm: 0.5 – 120  m 300 mm: 1.2 – 300  m The number of detectors is critical for high resolution Physical Pharmacy 210

Physical Pharmacy 211 Dynamic Light Scattering A.k.a. Photon Correlation Spectroscopy

Physical Pharmacy 212 DLS Principle

Physical Pharmacy 213 PCS setup

Physical Pharmacy 214 Characteristics of PCS/DLS

Physical Pharmacy 215 Laser Source for DLS

Physical Pharmacy 216 Factors influencing scattering intensity

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21 References htm SD Duke, RE Brown, EB Layendecker, “Calibration of spherical particles by light scattering”, Duke Scientific Corporation, Technical Note-002B, May 15, 2000.