• For Solid Samples:
  • Minimum Particle Size (Powders): 25 μm
  • Sample Cells Available: Cylindrical, Adjustable-Gap, Clamping
  • Irregular sample geometries and nonplanar samples are not well suited for this measurement
• For Liquid Samples:
  • Required Sample Volume: 2 mL
  • Particle Size Range: 3.8 nm to 100 μm
  • Maximum Sample Concentration: 70 % w/v

Particle Zeta Potential:

In particles, zeta potential is measured in solution-state using Electrophoretic Light Scattering (ELS). ELS is a variant methodology of Dynamic Light Scattering (DLS) and is likewise used to measure the speeds of solute particles.

Unlike standard DLS, ELS evaluates particle kinetics in response to an oscillating electric field. The field induces electrophoretic movement that yields a slight frequency shift in the scattering laser beam.

A collection of specialized detectors measures the magnitude and frequency of these shifts against a reference laser beam, and the resulting outputs are correlated to particle mobility and zeta potential.

Solid Zeta Potential

In solid (macroscopic) samples, instruments instead measure Streaming Potential to interpolate zeta potential. In this technique, a solid, electrochemically active material is mounted to form a capillary channel. Then, a solution of electrolytic ions is passed through the channel under the influence of a controlled pressure gradient.

As they flow, the ions induce electrophoretic effects in the slipping plane of the sample surface, causing charge carriers in this layer to rearrange.

The system measures the resulting change in electrical potential as a function of electrolyte strength and uses this data to calculate the zeta potential of the sample.