This is a copy of the slides presented at the meeting but not formally written up for the volume.

Analytical ultracentrifugation (AUC) is a first-principle means to determine the molecular weight and size distribution of dissolved particles. Though primarily used for characterizing biomaterials, AUC also is used in polymer chemistry to determine size distributions and density distributions of latices, pigments, polymers and co-polymers. In fact, AUC can provide useful information for virtually any solute in a wide range of solvents. The methods are non-destructive, allowing subsequent analyses on the same sample. There are two different AUC methods-velocity and equilibrium. The principles of equilibrium and velocity sedimentation will be described, along with their advantages and disadvantages relative to one another and relative to other methods.