Centrifugation: To find the RPM to set a particular rotor at for a specific RCF:

Centrifugation is an important step in pretty much every protein chemical and molecular biological procedure. The force exerted on a particle in a centrifuge is a simple function of the rotation speed of the centrifuge and the radius of rotation. The actual equation is RCF = 1.12R(RPM/1000)2, where RCF = relative centrifugal force, R is the radius of rotation measured in millimeters and RPM is the number of rotations per minute. RCF is the same as G force essentially; an RCF of 100 would be equivalent to a gravitational field of 100G. The R in this equation must be measured in millimeters, and can be measured at the top of the tube (RMin), the middle of the tube (RAv) or the bottom of the tube (RMax). Since protocols often don't specify which value they mean, you may have to take your best guess as to which one to use. If you are trying to pellet something out, you should probably use RMax, since the pellet obviously froms at the bottom of the tube. This particular program will calculate the RPM you need to set to get a particular RCF if you also enter the R value. To calculate the RCF you get from a particular RPM from a particular sized rotor go here

Enter the R value (radius of rotation) for the rotor in mms:
Enter the desired RCF:   

Disclaimer; This program was constructed primarily to save time for busy researchers around the world. We hope you find it useful, and we are confident that it is accurate and reliable. However, we cannot be held responsible for any problems which may arise as a result of the use of this program.

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