In traditional DLS experiments, the scattered light is detected at a single angle and then auto-correlated to determine the diffusion rate of the particles, and ultimately the particle size distribution. Since the direction and the number of photons scattered depends on the size of the particles, for mixed particle sizes a single angle result may misrepresent the true particle size population. Multi-angle dynamic light scattering (MADLS) overcomes many of these drawbacks by automatically combining correlograms from multiple measurement angles to give a robust, angular independent result, with improved resolution, which is suitable for comparison with data from orthogonal techniques. In this webinar we will explain the basic principles behind the MADLS measurement on the Zetasizer Ultra and provide measurement examples.