Centrifuges

The centrifuge is a commonly used tool in laboratory research. It uses centrifugal force to separate substances in liquid or solid media according to particle size and density differences. Centrifugation may present two serious hazards: mechanical failure and dispersion of aerosols. Therefore, training on how to use the centrifuge properly and safely is essential for all new employees as part of Lab-Specific Training.

Safe Procedures for Centrifugation

Before Centrifugation

Train each operator on proper operating procedures, review the user manual

Use only rotors compatible with the centrifuge. Check the expiration date for ultracentrifuge rotors

Check tubes, bottles, and rotors for cracks and deformities before each use

Make sure that the rotor, tubes, and spindle are dry and clean

Examine O-rings and replace if worn, cracked, or missing

Never overfill centrifuge tubes (don't exceed ¾ full)

Always cap tubes before centrifugation

Always balance buckets, tubes, and rotors properly

Check that the rotor is seated on the drive correctly, close the lid on the centrifuge, and secure it

When using swinging bucket rotors, make sure that all buckets are hooked correctly and move freely

During Centrifugation

Keep the lid closed at all times during operation. Never open a centrifuge until the rotor has stopped

Do not exceed safe rotor speed

The operator should not leave the centrifuge until full operating speed is attained and the machine appears to be running safely without vibration

Stop the centrifuge immediately if an unusual condition (noise or vibration) begins and check load balances

After centrifugation

Allow the centrifuge to come to a complete stop before opening

Wear gloves to remove rotor and samples

Check inside of centrifuge for possible spills and leaks, clean centrifuge and rotor thoroughly if necessary

Wash hands after removing gloves

Centrifuging Infectious Materials or Human Samples

Follow the safety procedures above, plus:

Place a biohazard label on the centrifuge

Always wear gloves when handling tubes or rotors

Avoid the use of celluloid tubes with biohazards. If celluloid tubes must be used, an appropriate disinfectant must be used to decontaminate them

Always use sealed safety cups, safety buckets, or sealed rotors with O-ring as secondary containment if available

Fill centrifuge tubes, load into rotors, remove from rotors, and open tubes within a biological safety cabinet if biological safety cabinet is available

Wipe exterior of tubes or bottles with disinfectant prior to loading into rotor or bucket. Seal rotor or bucket, remove outer gloves, and transport to the centrifuge

Always wait at least 10 minutes after the run to allow aerosols to settle before opening the centrifuge. Check for possible spills or leaks

Decontaminate centrifuge interior, safety cups or buckets, and rotors if tube breakage occurs

Include centrifugation procedure and decontamination plan in lab SOPs

Centrifuge Maintenance

Moisture, chemicals, strong cleaning agents, and other substances can promote corrosion of centrifuge parts and cause centrifuge failure. The following are general maintenance recommendations:

Follow manufacturer instructions for maintenance and cleaning
Keep the centrifuge clean and dry
Cleanup all non-infectious spills immediately
Decontaminate the rotor after use with biological or radioactive materials. Use 10% bleach for 30 minutes followed by 70% ethanol and let air dry to clean rotors and cups
Never clean rotors and associated parts with abrasive wire brushes
Store the rotor upside down in a dry place, with lids or plugs removed to prevent condensation
Remove adapters after use and inspect for corrosion
Inspect rotor regularly. Remove rotors from use that show any sign of defect, and report it to a manufacturer's representative for inspection

Maintaining a Log Book

To avoid rotor failure, keep a log book for high speed rotors recording the length of time and speed for each use. Track and discard rotors according to the manufacturer's recommended schedule.

Centrifuge Emergency Procedures

The following events are considered an emergency:

If there is a spill in the centrifuge
If centrifuge malfunctions
If there is a rotor failure
If there is a tube breakage

Emergency Procedures

Turn centrifuge off immediately and close the centrifuge lid
Notify others and evacuate the lab
Close the lab door
Post a biohazard spill sign at the lab door
Leave for 30-minutes to reduce the risk of aerosols
For spill cleanup, the operator must wear proper gloves, remove debris, clean and disinfect centrifuge interior, rotors, safety cups or buckets following the manufacturer's instructions
Place any contaminated protective clothing, gloves, and all cleanup materials in a biohazard bag
Wash hands and any exposed skin surfaces with soap and water
Seek medical attention as necessary
Report incidents to P.I. or lab supervisor and the Office of Safety. Call Lab & Research Safety Officer 701.777.3341 for assistance