Determining the Surface Charge from Electrokinetic

10 DETERMINING THE SURFACE CHARGE FROM ELECTROKINETIC MEASUREMENTS 

In the quantitative sections of this chapter the primary emphasis has been on establishing the relationship between the electrophoretic properties of the system and the zeta potential. We saw in Chapter 11 that potential is a particularly useful quantity for the characterization of lyophobic colloids. In this context, then, the f potential is a valuable property to measure for a lyophobic colloid. For lyophilic colloids such as proteins, on the other hand, the charge of the particle is a more useful way to describe the molecule. In this section we consider briefly what information may be obtained about the charge of a particle from electrophoresis measurements. 

10a Relation Between Surface Charge and Zeta Potential 

Integrating this expression over the entire double layer gives 

Substituting this result into Equation (80) gives 

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