In automatic mode, the software selects the most suitable analysis to find the zeta potential of your sample under the present conditions. If the conductivity of the sample is high, only the Fast Field Reversal technical will be applied. This technique provides a mean zeta potential. In order to obtain a distribution the Slow Field Reversal also has to performed. However, due to high conductivity and potentially resulting Joule heating/sample degradation, this is not done in automatic mode (Conductivity to switch to monomodal by default is 5 mS/cm). This setting can be overwritten by either using Configure for the Automode and changing the limit or by selecting General Purpose (which will produce a distribution up to 0.15M salt)

There is nothing wrong about your measurement, and in many cases the mean zeta potential is the main parameter of interest.

http://www.materials-talks.com/blog/2015/09/24/zeta-deviation-larger-than-the-mean-how-can-that-be/

http://www.malvern.com/en/support/resource-center/technical-notes/TN101104ZetaPotentialQualityReportZetasizerNano.aspx

Thank you Ulf. It makes more sense now as I went back and looked at all of other experiments and readings I have taken keeping this in mind.

May I know why my Zeta Potential graph is not smooth enough and is very wide?

But my zeta potential values are fine with good stability.

Kirubhashni Lognathan Please repost your question as a new one and provide images of your graphs, details of the sample, instrument etc.

Hi Kirubhashni Lognathan , without specific details on your ssample, you may find the generic discussion in these two blogs on zeta deviation (=width of the zeta graph) of interest:

• https://www.materials-talks.com/what-is-the-zeta-deviation/
• https://www.materials-talks.com/zeta-deviation-larger-than-the-mean-how-can-that-be/

The same thing occurred with me

@Ulf Nobbmann

And treated it by several washing the powdered sample then centrifugation

Then resuspend it again and measure.