A new method for the rapid determination of the averaged size and an index of polydispersity of submicron particles in liquids using laser light-scattering spectroscopy

Abstract

Laser light-scattering spectroscopy, also known as light-beating spectroscopy, is a new technique for measuring the diffusion constant of macromolecules or the size of particles in suspension [1, 2]. It makes use of the fact that the scattered light is subject to intensity fluctuations related to the (size-dependent) Brownian motion of the scatters. In this paper we describe a new particle-size meter1 1 Trade name: Coulter® Nano-Sizer™. based upon this principle. It incorporates the optical set-up for detecting the scattered light and the electronics for the time analysis of the intensity fluctuations. Both a mean particle size and an index of polydispersity are evaluated as final results. The instrument is designed for routine measurements of particles in the size range from 40 nm up to 3 - 4 μm and requires no calibration with known standards. The overall precision is better than 3% for a measuring time of two minutes. © 1980.