Pharmaceutical drug delivery & development, nano-plastics in seawater, waste-water treatment, desalinization, improving industrial-scale process efficiency, new theories of nanoparticle charge…The measurement of zeta potential of nano- and micro-particles directly in high and saturated ionic strengths has never been more important.

So, what’s the problem with high ionic strength measurements?

High ionic strength means very high electrical conductivity and a range of pathological effects are observed near to the measurement cell electrodes that can seriously degrade the measurement or even prevent it altogether! Malvern Panalytical’s simple diffusion barrier method uses a laboratory standard, long, thin, pipette tip to add the particles remotely from the electrode surfaces, preventing the catastrophic effects and allowing the measurement to proceed. You may even be able to re-collect the sample afterwards!

Taking the lead in the science of nanoparticle zeta potential

Using the new method, we have provided the first wide-ranging experimental verification of current zeta potential theory in saturated systems, even including highly counter-intuitive effects such as changes in the polarity of zeta potential! We have even discovered some previously unobserved effects and for the first time in half a century, experimentation is able to lead the way in nano-particle zeta potential research!

What does this mean for you?

As a Zetasizer Advance series user you are now able to characterise nano- and micro-particle charge in representative ionic strengths, in a simple measurement of a few minutes duration and the only additional equipment you will need is a disposable pipette tip!

If you would like to find out more about how the diffusion barrier method and constant current mode on Zetasizer Advance systems can be used to characterize zeta potential in saturated ionic strengths, read the free-access paper in Nature: Scientific Reports here.


  • Austin, J., Fernandes, D., Ruszala, M.J.A. et al. Routine, ensemble characterisation of electrophoretic mobility in high and saturated ionic dispersions. Sci Rep 10, 4628 (2020).