A laboratory centrifuge is used to separate two substances of similar density or when there are insoluble particles present in a solution. A laboratory centrifuge operates on the principle of sedimentation, whereby the acceleration of the rotor generates a centripetal force acting on the rotor and the centrifuge tubes.
As a result, the denser substances in the tubes are drawn outwards in a circular motion, whilst the lighter particles move towards the centre. In some cases, individual particles settle at the bottom of the centrifuge tubes. These particles are known as granules, whilst the clear solution is called the supernatant.
In the laboratory, a centrifuge separates plasma from blood cells, precipitates cells and purifies samples of mechanical impurities.
The answer to the question of why a centrifuge is needed in a laboratory is clear: the equipment ensures that the material is properly prepared for further analysis. Without the centrifugation stage, it is impossible to carry out most clinical and biochemical analyses.