We primarily use analytical ultra centrifugation (AUC) for validation purposes, and for the analysis of especially challenging samples after other characterization techniques had been tried (SEC and AF4). We operate AUC instrumentation with a wide range of rotors and cells, where the sedimentation of components is monitored 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:
Analytical ultra centrifugation (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. AUC is the golden method to compare against when it comes to validation of methods (alternately to size exclusion chromatography (SEC)). Typical uses of AUC are stability testing of proteins, aggregation analysis, batch to batch control, molar mass distribution.
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