What variables can affect accuracy of sedimentation and diffusion coefficient calculations?

• Location between the two menisci (i.e., it must be properly selected)
• Density of the solvent
• Temperature (affects viscosity)
• Concentration dependency (pure, non-associating solutes show a decrease in sedimentation coefficient with an increase in concentration)
• Radial dilution due to sector shapes
• Boundary analysis (concentration and shape)
• Speed dependence (sedimentation coefficient may increase with speed increase, and result in solute aggregation)
• Primary electrostatic charge of solute and solvent
• Association reactions that might occur between molecules as molecular weight increases