The Coulter Principle utilizes an electric field to draw particles across an aperture of defined size and measure the electric pulses generated. The pulses are converted for size distribution and concentration measurements of particle suspended solutions. 

Photon Correlation Spectroscopy (PCS), also referred to as dynamic light scattering, is a technique used to determine the diffusion coefficient of small particles in a liquid.

Measuring the size of particles in suspended liquids or in dry powder format can be accomplished using particle size analysis based on light scattering techniques.