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How to choose the right centrifuge for your work
Speed is not the only number that matters. This article explains rpm versus RCF and how to match the rotor to your sample.
The most common question when choosing a centrifuge is “how many rpm do I need?” — and it is an incomplete question.
rpm versus RCF
rpm is motor speed. RCF (relative centrifugal force) is the force actually applied to the sample, and it depends on rotor radius too. Two machines at the same rpm with different rotors deliver different RCF.
Good protocols therefore specify RCF or × g, never rpm.
Which rotor type?
- Fixed-angle — faster pelleting, suited to cell harvesting and general sedimentation
- Swing-out — flat separation layers, suited to blood fractions and gradients
Do you need refrigeration?
If you work with proteins, enzymes or other temperature-sensitive samples, choose a refrigerated model — high-speed spinning generates real heat.