Microcentrifuges: choosing by force and rotor fit rather than by speed, and when refrigeration and sealed rotors are genuinely required

Specifying it properly

1. Work in force, not revolutions. A protocol specifies relative centrifugal force because that is what acts on the sample, and the same rotational speed gives different force in rotors of different radius. Check the maximum force of the rotor you will actually use rather than the headline speed.
2. Tube fit and adapters. Standard microcentrifuge tubes are the base case, and strips, small tubes and larger tubes need adapters that may or may not exist for a given rotor. List every tube format the laboratory uses and confirm each before ordering.
3. Refrigeration, and whether you need it. Nucleic acid preparations, enzyme work and anything spun for an extended period benefit from cooling, and frictional heating is significant in a small high-speed rotor. Refrigerated units cost considerably more and take more bench space, so decide from the protocols rather than by default.
4. Sealed rotors for hazardous samples. Where human, infectious or toxic material is spun, a sealed rotor lid keeps an aerosol contained if a tube fails and allows the rotor to be opened in a cabinet. Confirm the sealed option exists for the rotor you are buying.
5. Noise, footprint and where it sits. These machines live on a crowded bench and are used constantly, so noise level, footprint with the lid open and lid action all matter more than they appear to. A machine nobody wants to sit beside gets moved somewhere inconvenient.

Quick spins and the everyday reality

Much microcentrifuge use is a short spin to collect liquid from a lid or a wall, for which a small unpowered or low-speed mini centrifuge at a fraction of the price is usually better placed and faster to use. Many laboratories buy one full instrument and queue at it.

Having a mini centrifuge beside the bench and a full instrument shared is usually a better arrangement than two full instruments, and it costs less.

Balance, maintenance and failure

Unbalanced loads are the standard failure mode, and while imbalance detection protects the machine it does not remove the need to balance properly. Train for it, and keep balance tubes at the instrument.

Rotors corrode, particularly with salts and guanidine, so wipe up spills and inspect periodically. A corroded microcentrifuge rotor at speed is a genuine hazard rather than a maintenance nuisance.

Common questions

How fast does a microcentrifuge need to be?

Check the relative centrifugal force of the rotor you will use rather than the advertised speed, because force is what protocols specify and it depends on rotor radius as well as speed.

Do I need a refrigerated microcentrifuge?

For nucleic acid preparations, enzyme work and long spins, yes, since frictional heating in a small high-speed rotor is significant. For routine short spins at ambient it is an unnecessary cost.

Will my tube strips fit?

Only with the right adapter, and adapters do not exist for every rotor. List every tube format in use and confirm each one before ordering rather than after.

When do I need a sealed rotor?

Whenever a tube failure could release an infectious or toxic aerosol, including most human sample work. A sealed lid also lets the rotor be opened inside a biosafety cabinet.

Browse by service class

• Compare Gene synthesis on advertised prices