Zeta Potential Analyzer Nicomp Z3000

Zeta potential is a measure of the charge on the surface of particles or emulsion droplets. This charge is an indication of dispersion stability. Dispersions with a zeta potential near zero are typically unstable and prone to aggregation or phase separation. A higher zeta potential indicates expected greater stability.  

Measurement

A sample is pipetted into a standard square cuvette and a dip cell containing two palladium electrodes is  inserted into the cuvette.  The electrodes apply an electric field, causing the particles to migrate to the pole of opposite charge. The direction of the particle motion indicates if the particles are positively or negatively charged. The speed of the particle motion is used to calculate the magnitude of the charge. 

The Nicomp measures the particle motion using a patented DSP based phase analysis light scattering (PALS) technique that is extremely sensitive and robust. Measurements can be made at low electric field strengths which is much more gentle on fragile samples such as proteins or other biomolecules. 

Applications

The most common use of zeta potential is in the formulation of new suspensions and emulsions. Both the particle size and zeta potential are useful indications of which formulations should prove more stable over time. Another application is the determination of what pH generates a zero zeta potential value – the Isoelectric point (IEP).