Electrophoretic Light Scattering (ELS)
ELS is a light scattering technology utilized to measure the zeta potential of particles suspended in solution via Doppler shifts in scattered light. When applying an electric field on the sample, the charged particles dispersed in the suspension undergo electrophoretic movement. Due to the Doppler effect, the scattered light experiences a frequency shift compared to the incident light. The magnitude of this shift depends on particles’ electrophoretic velocity. A detector set up at the forward direction detects the scattering signal and by which the frequency shift Δf and the electrophoretic mobility are obtained. Through Henry's equation, the zeta potential and its distribution can be obtained based on the obtained electrophoretic mobility.