ultracentrifuge
(rus. ультрацентрифуга)
—
a device used to separate particles of less than 100 nm size (colloids, subcellular particles, macromolecules of protein, nucleic acids, lipids, polysaccharides, synthetic polymers, etc.), suspended or dissolved in the liquid. This is achieved through rotor rotation that causes centrifugal field with acceleration, which exceeds the acceleration of gravity by many orders of magnitude.
Description
Ultracentrifuges can be divided into preparative, analytical and preparative-analytical ones by purpose and design. Preparative ultracentrifuges are equipped with angle rotors with sockets for cylindrical tubes, jars or bottles, inclined at a 20-40º angle versus the rotor’s vertical axis, or the so-called swinging bucket rotors with jars with 90º rotation. There are also zonal and flow rotors with a large inner cavity for fluid under fractionation. Preparative ultracentrifuges used to separate individual components out of complex media, such as viruses and subcellular organelles. Analytical ultracentrifuges are equipped with rotors with pass-through cylindrical sockets to house special transparent cuvettes for solutions or suspensions under testing. Theу can provide the very picture of the particle redistribution process immediately in the rotor by means of special optical systems (refractometric, absorption systems). There are many types of ultracentrifuges available in the market, where centrifugal acceleration of up to 1,000,000g is generated, and the separation of particles and molecules is carried out in the amount of as much as tens or hundreds of milliliters. Currently ultracentrifugation is actively used to determine the molecular weight distributions of macromolecules in solutions.
Authors
- Govorun Elena N.
- Shlyakhtin Oleg A.
Sources
- Colea J. L., Hansenb J. C. Analytical Ultracentrifugation as a Contemporary Biomolecular Research Tool // J. Biomol. Techn. V 10. 1999. P. 163–176.
- Ultracentrifuge Explosion Damages Laboratory. — www.ehrs.upenn.edu/programs/labsafety/ultra_explosion.html (reference date: 12.10.2009).
- Ultracentrifuge // Wikipedia, the free Encyclopedia. — http://en.wikipedia.org/wiki/Ultracentrifuge (reference date: 12.10.2009). Great Encyclopedic Dictionary. - Moscow: AST, Astrel, 2008. — 1248 P.