Seeing is Believing
Visualization is the underlying principle behind Zetaview^® which captures both Elecrophoretic and Brownian Motion in a laser scattering microscope. Multimodal zeta potential and size histograms can be derived from the analysis of thousands of individual particles (ranging from 80 nm to 10 µm) in a routine way, providing the classical micro-electrophoresis with a modern tool to study the interface behavior of colloid particles.

Electrophoresis and Brownian Motion
Zetaview uses a laser scattering microscope with video camera to capture the movement of fine particles in an electrophoresis cell. The electrphoretic mobility and Smoluchowski zeta potential are derived from the measurement of the particle velocity distribution. Using the Stokes Einstein formula, Brownian motion of the particles is analyzed to produce particle size distributions.

Technical
Laser light is directed into the focal point of a microscope lens at a 90° angle. The intensity of the scattered light from illuminated particles is sufficient enough that polystyrene latex particles as small as 80 nanometers are still visible. While actual upper and lower measurement limits are affected by the type of material, the maximum upper end size limit for all materials is 10 microns.

By automatically controlling the optics the electrophoresis movement is easily separated from the competitive electro-osmosis effect. Conductivities bigger than 1mS/cm may cause convection within the cell. This and other disrupting effects like drifts are detected through the video camera, enabling Zetaview's "seeing is believing" principle to provide significantly more reliable data than comparable techniques.

The mobility profiles and the mobility at the two stationary layers deliver comparable zeta potential values. The mobility profile reveals more of the sample condition quality, whereas high resolution zeta potential distributions can be obtained from the measurement at the stationary layers.

Validation
Zetaview's methodology relies on first principles and as such can be easily validated. Each automatic measurement can be verified by visual single particle measurements.

Total Solutions in Particle Characterization