Analytical ultracentrifugation

In an analytical ultracentrifuge (commonly abbreviated as AUC), a sample’s sedimentation profile is monitored in real time by an optical detection system.

The sample is detected via ultraviolet light absorption and/or interference optical refractive index sensitive system, monitored by light-sensitive diode array or by film in the older machines.

With AUC it is possible to gain information on the number and subunit stoichiometry of non-covalent complexes and equilibrium constants of macromolecules such as proteins, DNA, nanoparticles or other assemblies from different molecule classes.

To allow the light to pass through the analyte during the ultracentrifuge run, specialized cells are required which have to meet high optical standards as well as to resist the centrifugal forces.

[2] The size resolution of this method scales approximately with the square of the particle radii, and by adjusting the rotor speed of the experiment size-ranges from 100 Da to 10 GDa can be covered.

Spinco Model E Analytical Ultracentrifuge. This is an early instrument, dating to the 1950s. The operator is seated in front of the sample chamber, with his left hand touching the rotor. In operation, the chamber would be sealed behind an armored shroud and pumped down to vacuum. The shroud has been lowered to allow access for loading or unloading the rotor. [ 1 ]
Rotors for an Analytical Ultracentrifuge for a maximal spinning velocity of 50,000 (left) and 60,000 (right) rpm