Simultaneous Resolution of Three Particle Sizes in a Single Suspension by Using DLS

Dynamic light scattering (DLS) is a technique for determining the size of particles in a liquid suspension. Such particles undergo random or Brownian motion, the speed of which is directly related to the size of the particles; the smaller the particles, the faster they move. Polymer latex spheres can be used to verify DLS performance because they are available as well-characterized dispersions of near-perfect spheres. While DLS is a well-established technique for determining the average radius of a monodisperse sample, it is a significant challenge to distinguish particles with different sizes in a single suspension. The ability to resolve multiple particle sizes depends on several factors, including the sizes of the particles, their relative scattering intensities, the polydispersity of their size distributions, the quality of the sample preparation, and the quality of the data. This application note demonstrates the resolution of multiple particle sizes in suspensions of two and three different-sized particles by using the Litesizer™ 500.