Centrifugation, sometimes referred to as separation or force separation, is widely used in laboratories. A centrifugal force is applied to separate substances, cells, cell parts or fluids, for example, by weight, concentration, viscosity or other properties. The technology is based on the samples being arranged in the rotor of the centrifuge, which rotates them at a certain speed measured in revolutions per minute, for a certain time.
The power of centrifugation is a ratio of the radius of the rotor to the centrifuge and revolutions per minute (RPM) and is expressed as a multiple of g, or relative centrifugal force (RCF).
This can be described by this equation:
g = (1.118 × 10-5) x R x S2
Where g is the relative centrifugal force (RCF), R is the radius of the rotor in centimeters and S is the revolutions per minute (RPM)
Improperly ballanced or faulty centrifuge can be very dangerous. Take time to assess a few safety issues before proceeding.
For safety's sake it is better to make sure everything is in order before putting samples in the centrifuge. Is the rotor OK? Are swing buckets lithe? Is there no dirt or impurities in the rotor that affect it's balance. The larger the centrifuge and the higher the rotational speed, the greater the importance of such an checkup.
This also applies when the centrifuge has completed its run. It's best to give it a once over, check if the centrifuge is OK, that there has been no leakage because sometimes liquid can get out of the vials without them breaking. You are expected to leave the centrifuge as you found it.
It is important to balance the rotor carefully before starting the centrifuge. Since it is a centrifugal force at work, samples must be arranged in the rotor so that their weight is evenly distributed over the diameter of the rotor. The greater the centrifugal force, the more precise the equilibrium setting needs to be. Poorly balanced centrifuges start to vibrate as the speed increases and the vibrations continue to increase with the speed and can cause damage to the centrifuge and the risk of accidents if something happens, e.g. if glass vials break.
It must be ensured that the vials containing the samples are resistant to the centrifugal force applied to them. Vials are different and some are specially made to withstand centrifugation while others are not. It's sad to lose your samples because the vials broke in the centrifuge and it's also sad to have to clean the centrifuge. This is especially important when working with biological samples and the risk of infectious agents escaping if the vials break.
Be carefull not to overfill the vials, never more than approx. ¾ and then close them securely so that nothing escapes. Mist escaping from unlocked or poorly closed centrifuge vials can gradually cause corrosion in the centrifuge which ends up malfunctioning but such mist may also contain toxins or pathogens which must be controlled as the person working on the centrifuge can inhale them and it may not be healthy.
If a centrifuge fails or you suspect that it's malfunctioning, turn it off, unplug it and call a repairman. Do not take any risk.