A centrifuge is a device that uses centrifugal force to separate two or more substances of different density or mass (Figure 1).
Basis of Separation
Materials with heavier masses move faster and farther away from the central point than those with lighter masses.
A centrifuge consists of a fixed base and a center stem to which arms or holders containing hollow tubes are attached. When the device is turned on, arms spin around the center stem at a high speed.
In this process, heavier material is thrown outward within the tube, whereas, lighter material stays near center of the device.
Precipitate (pellet) gathers at the bottom of the tube rapidly and completely, due to increase in an effective gravitational force.
The remaining solution is called supernate or supernatant.
Rate of centrifugation is specified by the acceleration applied to the sample. It is typically measured in revolutions per minute (rpm) or relative centrifugal force (RCF).
Types of Centrifuges
There are four basic types of centrifuges.
- Small bench centrifuge
- Large capacity refrigerated centrifuge
- High speed refrigerated centrifuge
Applications of Centrifuge
- Centrifuge is an important equipment used in biochemistry or biotechnology. It is used for the separation of cell organelles and sub-cellular fractions.
- These are essential device in clinical laboratories and small medical facilities.
- Centrifuges are used to separate substances with different densities and are also used for removing chylomicrons.
- There are certain types of centrifuges with a batch rotor for pelleting, which allow steroid hormone assays, and separation of lipoprotein fractions for HDL, LDL and VLDL.