How can I transfer an existing centrifugation protocol to a new rotor, bottle, or tube?


Protocol transfer is a common occurrence when scaling up a process to higher volume or improving efficiency by increasing speed. Though the process of going through a series of calculations to transfer an existing protocol can be a daunting and time-consuming task, Beckman Coulter offers convenient software tools and online solutions to facilitate seamless protocol transfer.

Simplify Protocol Transfer

Speak the Same Language – RPM vs. RCF

Depending on the source, a centrifugation protocol may be described in units of RPM (revolutions per minute) or RCF (relative centrifugal field) – RCF is also known as g-force (x g) and is typically reported for the maximum radius (rmax). RCF and RPM can be interconverted using the rotor radius, though transferring a protocol to a new tube, bottle, or rotor requires additional information on the existing and new setups.

Equate g-Force with Performance – k-Factor

Switching from one rotor or tube to another often changes the rmin and rmax, and the maximum g-force does not capture efficiency. A metric called the k-factor considers pathlength and RCF to represent pelleting efficiency. The k-factor also accounts for run time and offers simple protocol conversions when using different rotors, tubes or bottles, adapters, and fill volumes.

Simplify Protocol Transfer – Available Tools

Properly transferring a centrifugation protocol requires more than simply matching RPM or RCF values, and tracking down rotor and tube dimensions can be a tedious process. Optima XPN ultracentrifuges include eXpert simulation software, including a streamlined tool for switching to new rotors or tubes. Additionally, the online rotor calculator offers pre-loaded specs to simplify protocol transfer.


Moving a centrifugation protocol to a new setup can be a chore to calculate by hand. Beckman Coulter offers tools to save you time and simplify protocol transfer. Click here to check out the rotor calculator tool, or to see the New Intellifuge Calculator in action click here. To explore other topics please visit