Analytical ultra centrifugation (AUC)

At SOLVE:

At SOLVE we primarily use AUC for validation purposes and for especially challenging samples that are difficult to characterize using other techniques. SOLVE operates an AUC instrument with a wide range of rotors and cells. We monitor the sedimentation of components by UV and interference optics (RI).

Principle:

Analytical ultra centrifugation (AUC) is a separation methodology that separates macromolecules and particles in solution. The separation is based on the macromolecule’s differential sedimentation velocity in a solution under the influence of a centrifugational field. The size and density of a compound determines its sedimentation velocity. Detectors such as UV allow monitoring the sedimentation of  a sample component.

Applicability:

AUC is a method applicable to a very wide range of compounds, such as proteins, nanoparticles, viruses, and polymers. The technique is applicable to compounds with molecular weight of ~ 1 000 g/mol and upwards. When it comes to validation of methods (especially SEC), AUC is often referred to as the golden standard to compare against. Typical uses are for stability testing of proteins, aggregation detection, quality control, molar mass distribution determinations, etc.

Pros

  • Very wide size range
  • High resolution
  • Quantitative
  • Native conditions (concentration and solvent)
  • Low shear and surface area

Cons

  • Highly specialized and expensive equipment
  • Requires experience for proper operation and data evaluation
  • Relatively long analysis times