Loading, balance, brake, and temperature

Use the rotor manufacturer's stated maximum RCF, RPM, tube type, adapter, and load limits rather than applying a setting carried over from a different rotor or centrifuge. Centrifuge a tube only in a carrier, insert, or adapter designed for that tube and that rotor, with the closure and fill condition permitted by the exact instructions for use. A tube that is over filled, under filled, or seated in the wrong adapter is a loading problem before it is a speed problem.

Balance opposing positions by matching the complete opposing load and position according to the rotor manual. Equal nominal liquid volume alone is not a universal balancing rule, because tube weight, cap, and adapter also contribute to the load at each position. An unbalanced rotor stresses bearings and seals and can produce breakage or an unsafe run even at a correct RCF setting.

Brake setting controls deceleration, not the calculated RCF. Whether a fast or slow brake disturbs an interface or resuspends a pellet has to be established in the specific method procedure, because the effect depends on the specimen and the separation being performed. Temperature during the run also matters for analyte and cell stability; some specimens require room temperature and others require refrigerated centrifugation, and that requirement comes from the test procedure, not from a universal rule.

Do not open the centrifuge until the rotor has stopped completely and the lid opens normally. Opening early, or forcing a lid, converts a routine run into a safety event before any result is even in question.

A correct RCF number does not excuse an unbalanced load, an unapproved adapter, or an early lid opening.