Litesizer 500: Combining Particle Size, Zeta Potential, and Refractive Index Measurements In One Instrument

The refractive index of the solvent is an extremely important parameter in performing accurate dynamic light scattering (DLS) and electrophoretic light scattering (ELS) measurements on particles in solution. This dimensionless number describes how light propagates through a substance. While the refractive index of many solvents has been previously measured and published, it is important to note that the refractive index is strongly dependent on light frequency and, to an extent, on temperature. Furthermore, the presence of particles in solution might modify the overall refractive index of the solvent. As such, using ‘standard’ refractive index values instead of actual ones will very likely result in inaccurate particle size values. 

The Litesizer™ 500 is the only DLS-based instrument on the market that permits a simple and straightforward measurement of the solvent refractive index using the same experimental set up as the subsequent scattering experiment. The refractive index results are directly incorporated into the DLS and ELS experiment by the software and do not require any data processing. Thus, the solvent refractive index can now be accurately measured at the exact wavelength and temperature of the DLS or ELS experiment, ensuring maximum accuracy for particle size and zeta potential results under all experimental conditions.


Recording available
Dr. Vinod Radhakrishnan (English)
Vinod Radhakrishnan

Dr. Vinod Radhakrishnan is a Senior Product Specialist with the Advanced Technical Center at Anton Paar USA.  Dr. Radhakrishnan’s areas of expertise includes surface charge and zeta potential, particle sizing using light scattering and laser diffraction, and surface area and porosity.  Dr. Radhakrishnan holds a Ph.D. in Chemical Engineering from Auburn University.

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