Basic principles underlying centrifugation

This basic illustration helps to understand the principles underlying centrifugation and centrifugal force, and this force related to gravity. The movement of any physical matter is governed by Newton s Laws of Motion, and when considering centrifugal force it is important to also consider the centripetal force. These two form the important action-reaction force pair of circular motion, where the 

If a particle of a given mass is subjected to a centrifugal force it will behave in a certain manner and as detailed earlier it will move through a solution in a defined way, which is given by the following formula  

As gravity also plays a role in sedimentation, this relates to the centrifugal force in a way dehned hy the following formula  

The relative centrifugal force (RCF) value is thus related to rpm - a popular way of reporting the speed of a given centrifuge with a particular rotor. However, rpm is not a very scientihc way of expressing the experimental conditions used, as it relates to the use of a specihc rotor. So when a different rotor is used with the same rpm any differences in angular velocity and radius 

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The basic principle is that the solid or semisolid sample is suspended into an aqueous solution and left under stirring to reach equilibrium of the analyte between the solid particles and water. In some methods, the solid phase is then removed by centrifugation, while in others, it is kept in the sample during the extraction. " ... 

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