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Q1: What is the basic mechanism of how a centrifuge separates mixtures?
A centrifuge rapidly spins a rotor containing samples, generating centrifugal force directed away from the axis of rotation. This force causes particles with different densities to separate, with heavier particles moving toward the bottom of the tube. The separation speed depends on particle size and density, making centrifugation much faster than gravity-based sedimentation.
Q2: How should centrifuge tubes be prepared before use?
Select tubes compatible with your centrifuge's maximum RPM and verify limits in the documentation. Inspect tubes for cracks or damage and ensure they are intact. Fill each tube to no more than three-quarters full to prevent spills, then balance tubes and cap them tightly before placing them in the rotor.
Q3: What precautions are necessary when centrifuging hazardous materials?
Wear appropriate personal protective equipment and prepare samples in a fume hood or laminar flow cabinet. Use secondary containment such as glass or plastic inserts for hazardous chemicals or biological samples. Sealed safety tubes provide an additional contained environment. Always ensure proper use of personal protective equipment when handling potentially dangerous materials.
Q4: What rotor inspection steps should be completed before centrifugation?
Verify the rotor is appropriate for your centrifuge and check that it and its cover are clean, dry, and free of cracks or deformities. Inspect O-rings for wear and examine the centrifuge spindle for bending or damage. Ensure the rotor is correctly seated on the spindle and that sample tubes fit snugly without gaps.
Q5: What should you do if unusual sounds or vibrations occur during centrifugation?
Immediately turn off the power button to stop the centrifuge. Evacuate the immediate area and allow the rotor to stop completely before approaching. Inspect samples for spillage and the rotor for abnormalities or imbalances. Do not attempt to restart until the cause is identified and resolved.
Q6: How should a centrifuge be decontaminated after use with biological samples?
Decontaminate the rotor with 10% bleach regardless of whether a spill occurred. Allow the bleach to stand for 30 minutes, then rinse with 70% ethanol and air dry completely. After decontamination, remove and inspect the rotor for damage and document your use in the logbook.
Q7: What is the proper procedure for cleaning up a centrifuge spill?
Clean the centrifuge immediately using appropriate personal protective equipment for any hazards present. Dispose of contaminated materials according to guidelines. Do not use abrasive brush wires, as they damage the rotor. For life-threatening hazards, alert emergency personnel and do not attempt cleanup yourself.