The ultracentrifuge is a centrifuge optimized for spinning a rotor at very high speeds, capable of generating acceleration as high as 1,000,000 G (9,800 km/s²) There are two kinds of ultracentrifuges, the preparative and the analytical ultracentrifuge. The second, however, is more theoretically important and we will focus on the discussion of the analytical ultracentrifuge. Theodor Svedberg invented the analytical ultracentrifuge in 1923, and won the Nobel Prize in Chemistry in 1926 for his invention.
With the analytical ultracentrifuge, the sample being spun is observable through an optical detection system that allows the operator to observe the sample concentration in real time during the experiment. With modern instrumentation, these observations are electronically stored and computerized and can be analyzed after the fact. Two kinds of experiments are commonly performed on these instruments, sedimentation velocity experiments and sedimentation equilibrium experiments. The first are sensitive to both the shape and molar mass of the sample being studied, whereas the second are insensitive to the shape, but are sensitive to the molar mass of the sample being studied.
The kinds of information that can be obtained from an analytical ultracentrifuge include the shape of macromolecules, the conformational changes in macromolecules, subunit stoichiometry of macromolecules, approximate molecular weights, and equilibrium constants for self associating systems.
Due to the tremendous amount of kinetic energy stored in the rotor of an operating ultracentrifuge, a catastrophic failure of the rotor's structural integrity (often thought to be caused by the use of improper or unrated rotors) at high speed is capable of causing an extremely violent explosion, sometimes completely destroying the machine. It is good practice, if possible, to leave the room of the centrifuge while it is in operation.