The Zetasizer Nano ZS is a high performance two angle particle and molecular size analyzer for the enhanced detection of aggregates and measurement of small or dilute samples as well as samples at very low or high concentration using dynamic light scattering (DLS) with Non-Invasive Backscattering (NIBS) optics. The use of NIBS provides significantly better performance than systems using 90˚ scattering optics. The system also incorporates a zeta potential analyzer that uses electrophoretic light scattering for particles, molecules and surfaces. Zetasizer Nano ZS is used for the measurement of size, electrophoretic mobility of proteins, and the zeta potential of colloids and nanoparticles.