This year marks my 25th anniversary of supporting Zetasizer users around the World. In that time, I have probably answered thousands of questions from Zetasizer users covering a wide range of topics. The Zetasizer range of products use the techniques of dynamic and electrophoretic light scattering to obtain particle and molecular size and the zeta potential of molecular solutions and colloidal dispersions.

Dynamic light scattering (DLS) is a non-invasive technique that measures the time-dependent fluctuations in the scattering intensity arising from a particle dispersion or molecular solution. The intensity of the scattered light fluctuates due to the random movement of the particles or molecules undergoing Brownian motion. Analysis of these intensity fluctuations using autocorrelation determines the translational diffusion coefficients and subsequently the hydrodynamic size using the Stokes-Einstein relationship.

Electrophoretic light scattering (ELS) measures the frequency shift of scattered light from particles or molecules undergoing electrophoresis and enables the measurement of zeta potential. The zeta potential of a particle is the overall charge that the particle acquires in a particular medium and can be used to predict the stability of the dispersion and provide insights into the surface chemistry of the particle being investigated.

The Zetasizer instrument is a very easy-to-use system that can generate large amounts of results very rapidly. You do not have to be an expert to measure a sample containing nanosized particles or macromolecules and obtain data that may be key to your research or workflow. However, have you ever wondered what a certain parameter in the software means? Or how does the instrument actually measure the size of a molecule less than 1 nanometre in diameter? Perhaps you have wondered what is the best way to prepare your samples for measurement? Or how to set up the measurement in the software?

Get the best out of your particle sizing and particle charge measurements

On October 27th we are holding another Ask an Expert! webinar in which we will cover frequently asked questions for the Zetasizer. This is a great opportunity for a Zetasizer user to ask those questions you have always wanted to ask but perhaps were too embarrassed to do so!

You can ask your question by emailing or by using the #MPexpert hashtag on Twitter. No matter whether you are a novice user or an experienced Zetasizer operator, there will be something for everyone. I look forward to receiving your questions and seeing you at the webinar.

Previously in the ‘Ask an Expert’ series: