Sir,

The basic idea of getting a good zeta potential measurement is to achieve a single particle suspension for which sample preparation plays an important role. If your particles stick to one another, this will lower the zeta potential as there will be less surface charges to measure. Ultrasonication of TiO2 particles can be useful for this but above all I would suggest you to find the best suited solvent or buffer for TiO2 particle of interest. Also, make sure that your concentration is high enough to detect a signal but low enough to prevent aggregation. Another important factor is Temperature which can play a role too, experiment with higher or lower temps if you have temp control in your zetasizer and also check the pH of the suspensions as this can play a role in protonation of free electrons in your sample.

Dear John,

add Zeta potential within the keywords. The competent employees of a specific company love to respond such questions.

From my experience I suggest performing a number of PH dependent series of zeta potential measurement starting in the strong acid or basic range. Keep the ionic strength high (1st so that the variation is small, 2nd to reduce the size of the double layer (in reality you are interested in the surface charge not in the charge of the moving ionic cloud)) and the concentration as low as possible. The MSDS often helps to recognize the preparation process of the TiO2. References and zeta potential measurements can be found in the publications.

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Than you for the feed backs