What steps constitute a safe centrifugation run, and how do you interpret completion indicators?

• A. Balance the rotor, ensure tubes are capped, select correct speed and time, run; after completion allow rotor to stop and inspect for leaks or spills before opening.
• B. Start at maximum speed immediately without balancing.
• C. Open the rotor while it is spinning to check contents.
• D. Ignore leaks after the run.

Answer: (A)

In centrifugation safety, the key on a run is to prepare and monitor everything to prevent mechanical failure and spills, then verify the run ended safely before handling samples. Start by balancing the rotor with matching tubes and volumes so the load is even. Securely cap the tubes to prevent leakage or aerosol formation if there’s any breakage or tube failure. Choose the correct speed (often given as relative centrifugal force or rpm) and time based on the protocol, ensuring the parameters suit the samples and rotor type. Run the centrifuge as specified, and when the cycle ends, allow the rotor to come to a complete stop before attempting any access. Once it’s stationary, inspect for leaks or spills around the rotor and tubes, and ensure there are no unusual noises, vibrations, or cracks in the rotor or lids before opening.

This option best reflects safe practice: balancing and containment during the run, using appropriate parameters, and confirming completion with a full stop and leakage check. The other approaches ignore crucial safety steps—starting without balancing, opening a spinning rotor, or ignoring leaks all pose serious risk to personnel and equipment and could compromise results.