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4.2.1. Ultracentrifugation
An ultracentrifuge is a centrifuge that spins a rotor at very high speed at centrifugal force of 1,000,000 g, equivalent to 9,800 km/s². They are used in molecular biology, biochemistry and polymer science for quantitative measurement of sedimentation velocity or sedimentation equilibrium or for the separation of solutes in liquid solution. There are two types od ultracentrifuges: analytical ultracentrifuge and preparative ultracentrifuge. Theodor Svedberg invented the analytical ultracentrifuge in 1923 and won the Nobel Prize in Chemistry in 1926. The vacuum ultracentrifuge was invented by Edward Greydon Pickels which reduced friction generated at high speeds and maintained constant temperature. Spinco introduced the first preparative ultracentrifuge with a centrifugal field of 40,000 rpm in 1949. Spinco was later purchased by Beckman instruments in 1954. |