I have used four different solvents: water, ethanol, propanol and methanol at different dilutions and various concentration of graphene oxide and reduced graphene oxide. In all these cases, the zeta potential shows a mean value of ZERO. Is there another solution in which I should disperse these particles.
Generally the Zeta potential for both these materials should be negative (-30 mV to -60 mV) at pH 7.
A couple of points:
1. The zeta potential depends on the dispersion medium
2. The measurement depends on the abilities of the instrument.
So, which instrument are you using? Where do you get the typical -30 to -60mV from?
Please provide more info about your sample and instrument.
John Francis Miller Hi John...thank you for raising the points.
I am using Malvern zetasizer instrument.
-30 mV to -60 mV is the reported values from many research articles. However, I am getting value close to Zero everytime.
I recommend you post an example of the results and the quality reports (depending on the version of the instrument). These can reveal many issues that may be giving you unexpected results.
Alexander Malm and @Alan Rawle are two of the Malvern Zetasizer experts who will know how to best interpret them.
Thanks for the tag John Francis Miller
Hi Pratik Kumar
The nature of zeta potential analysis means that if the instrument is not properly detecting appropriate scattering, the resultant signal appears to be noise and a value close to zero is reported.
The zetasizer software has an expert advice tab which should give some indication on how you may be able to improve your measurement. but if you are able to share some of the data, including the plotted charts, it may be easier to give some specific advice.
As John mentioned, Zeta potential is a property of the particle and the environment that it is in, so changing the dispersion medium will also change the zeta potential, so I would check what conditions the measurements were performed in when your quoted values of -30 to -60 mV were determined.
May I also ask what cell type you were using?
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