Automatic determination of zeta potential isoelectric point

Testa Analytical Solutions reports on how automation of isoelectric point measurement can be achieved using a BI-ZTU autotitrator in combination with a Nanobrook zeta potential analyser.

The stability of a dispersion is commonly determined by zeta potential. However, the surface chemistry of solid particles in a dispersion can be modified by altering parameters such as pH, surfactant concentration and salt concentrations. Hence, it is important to determine how pH affects the zeta potential of a dispersion. By studying the isoelectric point, scientists can determine how pH affects zeta potential and therefore can determine at which pH the zeta potential is zero.

The BI-ZTU autotitrator option for NanoBrook zeta potential analysers is ideal for automatic determination of the isoelectric point of colloids, for the detection of the onset of aggregation as a function of pH and for measure effect of salt concentration (ionic strength) on zeta potential. Incorporating four pumps the autotitrator provides high flexibility for optimising reagent use. Using an autotitrator enables automatic addition of acid or base to adjust the pH of the sample, recording of pH, and loading of sample into the electrode cell of a Nanobrook zeta potential analyser. This set-up allows users to determine zeta potential at a particular pH and then automatically repeat the measurement for the next pH in the series. 

By minimising manual labour requirements using the BI-ZTU in combination with the Nanobrook zeta potential analyser the cost of isoelectric point determination is greatly reduced.

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