Electrophoretic Light Scattering (ELS) is a technique used to measure the electrophoretic mobility of particles in dispersion, or molecules in solution. This mobility is often converted to Zeta potential to enable comparison of materials under different experimental conditions.

The fundamental physical principle is that of electrophoresis. A dispersion is introduced into a cell containing two electrodes. An electrical field is applied to the electrodes, and particles or molecules that have a net charge, or more strictly a net zeta potential will migrate towards the oppositely charged electrode with a velocity, known as the mobility, that is related to their zeta potential.

Malvern Instruments offer leading instrumentation for the measurement of electrophoretic mobility. The Zetasizer Nano provides a simple, fast and accurate way to measure zeta potential, and uses a unique disposable capillary cell to ensure that there is no cross contamination between samples. The NanoSight NS500 measures electrostatic potential particle-by-particle to produce number-weighted, not intensity-weighted, data, avoiding any bias towards larger particles.