Dynamic Light Scattering (DLS)

Dynamic Light Scattering (DLS)

Dynamic Light Scattering (DLS) measures the average size and size distribution of particles and colloids in solutions. Particles suspended in a liquid are constantly undergoing Brownian (random) motion, and the size of these particles directly affects their speed. Smaller particles move faster than larger ones. A laser light source in DLS passes through a liquid sample and scatter as particles or colloids come into its path. The scattered light is detected and recorded at some pre-defined angles. The time dependence of the scattered intensity can be correlated to particles speed; hence, average size and size distribution can be determined.

Recommended Usage and Guidance

What our DLS services are great for:

 

  • Particle size as a function of time, temperature, concentration and pH

  • Formulation development, process development

  • Average size and size distribution of dispersion, emulsion and suspension

  • Performance-related parameters such as refractive index, transmittance, opaqueness, transparency

  • Dosing and titration monitor, settling and aggregation indicator

Our technical team is happy to clarify on what technique will provide you with the best data.

EXAMPLE OUTPUTS 

DLS Anton Paar
DLS of a trimodal polystyrene latex sample containing particles of 22, 100 and 700nm in the ratio of 3:1:1. Credit: Anton Paar

INSTRUMENTS USED FOR
DLS

Anton Paar Litesizer™ 500

  • Measuring Range –   0.3 nm to 10 µm
  • Sensitivity –   0.1 mg/mL (lysozyme)
  • Max. Sample Conc. –   40% w/v
  • Operating Temp –   10° C to 35°C
  • Accuracy –   Better than +2% on certified reference material
  • Repeatability –   Better than +2% on certified reference material
  • Min. Sample Volume –   1.5 mL
  • Measurement Angles –   15°, 90°, 175°