In the field of life sciences, centrifugation is an indispensable technical means and the most common experimental item in the laboratory. Laboratory partners often ask, the centrifuge units labeled by each centrifuge tube are different, how to distinguish and compare?
01 centrifugal force
The principle of centrifugal technology is to use the strong centrifugal force generated when the object rotates at high speed to settle or float the suspended particles placed in the rotating body, so that some particles can achieve the purpose of concentration or separation from other particles.
Some biological particles can be separated by a gravity field (1×g), such as human blood cells, where treated blood cells are placed on the table for 1-2 hours, and white blood cells and red blood cells can be automatically stratified due to the different sizes of different cells. However, to separate smaller biological particles, a force much greater than gravity is required, usually we call this force centrifugal force, we can use centrifugal technology to separate different particles by rotating a centrifuge tube containing suspended particles along the axis. The centrifuge tube is rotated by a centrifuge, and the rotor is loaded and driven along the shaft, and the particles move outward from the axis under radial centrifugal force. The centrifugal force of both cells and biological macromolecules can be calculated by the following formula:
（1）F centrifugal force=m×rw²
F centrifugal force: the centrifugal force to which the particles are subjected;
m: the quality of the particles;
ω: angular velocity;
r: centrifugal radius, i.e. the distance from the axis of rotation to the pellet.
02 Relative centrifugal force
Typically, the radial force on a rotating rotor is measured by the relative centrifugation force (RCF). The so-called relative centrifugal force is the ratio of centrifugal force to gravity, expressed by the following formula:
03 The relative centrifugal force vs. rotational speed
ω is the angular velocity of the rotor, which refers to the number of degrees of arc per second that the rotor turns, and its value is:
（3）ω=2πRPM/60=0.10472RPM
RPM: The number of revolutions per minute that the rotor turns.
Combining Equation (2) and Equation (3) can be used to obtain the relationship between the rotational speed of the same rotor and the relative centrifugal force:
04 illustrate
Taking Amngent's centrifuge tube as an example, the centrifugal force of Amngent's 15ml centrifuge tube is 9400G, when the centrifugal radius is 8cm, that is, 80mm, substitute formula (4),
We can calculate that the relative centrifugal force is about 20000g.
Since the internal test standard of Amngent is 15ml centrifuge tube to reach 11000g to ensure the relative centrifugal force of 9400g under various use conditions, and the test standard used by Amngent 50ml centrifuge tube to reach 8400g is 10000g, so when using Amngent 15ml centrifuge tube to meet the needs of 9400g relative centrifugal force when experimenting, you can also use this tube with confidence and boldly!
