Operators can attain usable, detailed data without needing to have significant expertise.This relationship shows how size can be determined from diffusion speed provided that the temperature and continuous phase viscosity of the sample are known. Where D = Diffusion speed, k = Boltzmann’s constant, T = absolute temperature, η = viscosity, and D H = hydrodynamic radius. The relationship between the speed of Brownian motion of a particle and that particle’s size is defined by the Stokes-Einstein equation: The speed of Brownian motion can be directly measured from the scattered light pattern produced by the moving particles, a technique known as photon correlation spectroscopy (PCS) or quasi-elastic light scattering (QELS) but presently referred to as DLS. DLS is driven by collisions with the solvent molecules present, which are in constant movement due to their thermal energy. Small particles in a dispersion or solution are subject to Brownian motion. This article examples the benefits and limitations of DLS, focuses on those aspects of system design that are crucial in defining performance. The observation of scattered light helps determine defining characteristics of a particle dispersion or molecular solution such as particle size, molecular weight and zeta potential. Sponsored by Malvern Panalytical Oct 18 2013ĭynamic light scattering (DLS) is a valued sizing technique for proteins, colloids and dispersions, which comfortably extends to the sub 1 nm region.
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