The zetasizer nano ZS (Malvern Instruments) provides the ability to study the size, zeta potential and stability of particles in solution. These properties can be studied as a function of the pH, additives or dilution by an autotitrator. The size of particles is measured in the range of 0.6 nm à 6 µm on the basis of the Brownian motion of the particles using dynamic light scattering (DLS). The analysis is based on the speed of movement which depends on the size of particles. The zeta potential which refers to the charge surface of particles is measured by Laser Dopler Electrophoresis technique. It consists in the analysis of the speed movement of particles in a liquid when an electrical field is applied, i.e. its velocity.