Centrifuge: Uses and How to Use It
Centrifuge: Uses and How to Use It
A centrifuge spins samples very fast so that centrifugal force separates components by density: heavier particles or cells settle at the bottom of the tube and lighter liquid stays on top. Speed is given in rpm or relative centrifugal force (× g).
What is a centrifuge used for?
- Separating serum or plasma from blood cells.
- Pelleting cells, bacteria or chemical precipitates from solution.
- Separating nanoparticles or materials from solvent during washing.
- Collecting droplets at the bottom of microtubes (spin down) before PCR.
Parts of a centrifuge
- 1Locking lid – cannot be opened while the rotor spins
- 2Rotor – fixed-angle or swing-out; holds the tubes
- 3Control panel – sets speed, time and temperature (refrigerated models)
How to use a centrifuge
Fill tubes to the same volume
Use centrifuge tubes rated for the rotor and speed. Fill each tube to the same volume (1), within its maximum fill, and close it tightly.
Place tubes opposite each other to balance
Load tubes in pairs directly opposite each other (1). With an odd number of samples, add a balance tube filled with water to the same mass.
Close, set speed and time, then start
Fit the rotor lid (if any) and close the centrifuge until it locks. Set the speed (rpm or × g) and time on the panel (1), then press start. Never exceed the rotor's maximum speed.
Wait for the rotor to stop completely before opening
When the run ends, wait until the rotor has completely stopped and the lid unlocks by itself. Never stop the rotor by hand or force the lid open.
Common mistakes
- Running unbalanced: it vibrates hard, walks across the bench and can damage the drive shaft.
- Using ordinary or cracked tubes at high speed: they break and spray the sample around the chamber.
Care and safety
- Clean spills from the rotor and chamber, then leave the lid open to dry.
- Inspect the rotor for cracks or corrosion and log the number of runs if the maker requires it.
SOP for using a centrifuge
A summary of the standard operating procedure (SOP) for a centrifuge that your laboratory can adapt. Each step is explained in the how-to section above.
1Protective equipment
- A buttoned, long-sleeved lab coat.
- Safety glasses; goggles where corrosive splashes are possible.
- Nitrile gloves; for infectious material use sealed (aerosol-tight) rotors or buckets.
2Before use
- Only users trained by the instrument supervisor may operate it alone; read the manufacturer's manual.
- The centrifuge stands on a sturdy, level bench with about 30 cm clearance around it.
- The rotor is correctly seated and clean; tubes are uncracked and rated for the speed.
- Tubes are paired opposite each other with equal mass; use balance tubes if needed.
3Procedure
4After use
- Wait for the rotor to stop completely and remove tubes gently so pellets are not disturbed.
- Check for leaks; clean the rotor and chamber and leave the lid open to dry.
- Switch off and record the run in the log.
5Verification & calibration
- Check speed with an optical tachometer and temperature (refrigerated models) periodically.
- Periodic service and electrical safety test by a technician as the manufacturer recommends (usually once a year).
6Emergencies
- Heavy vibration or abnormal noise: press stop, do not open until the rotor stops, then check the balance.
- Broken tube with infectious material: leave the lid closed at least 30 minutes for aerosols to settle, then decontaminate wearing full PPE.
- Smoke, burning smell or electric shock: switch off at the socket if safe, never use water, use a CO₂ extinguisher and report it.
A print-ready version with purpose, scope, illustrated procedure, verification and sign-off boxes. Fill in your own document number and effective date.
Download the SOP (PDF, A4)Types and sizes
Mini centrifuges for spinning down microtubes; high-speed microcentrifuges (about 12,000–15,000 rpm) for 1.5–2 mL tubes; low-speed benchtop centrifuges for 15–50 mL and blood tubes; refrigerated centrifuges for temperature-sensitive biological samples. Fixed-angle rotors pellet faster; swing-out rotors give flat layers.
Centrifuge at AMI Scientific
Examples of centrifuge available in our store. Prices exclude VAT.
Sentrifus Mini Joan Lab MC-4/7SFrom Rp3.014.000
Sentrifus Kecepatan Tinggi Joan Lab MC-10PROFrom Rp4.974.000
Sentrifus Kecepatan Tinggi Joan Lab MC-12PROFrom Rp8.957.000
Sentrifus Microplate Joan Lab LC500-MPFrom Rp9.882.000
AMI Scientific supplies laboratory glassware, instruments and chemicals with tax invoices and delivery across Indonesia.
Frequently asked questions
What is the difference between rpm and × g?
rpm is revolutions per minute, while × g (RCF) is the force on the sample. RCF = 1.118 × 10⁻⁵ × r (cm) × rpm², so the same rpm gives different forces in rotors of different radius.
Why must centrifuge tubes be balanced?
An unbalanced load makes the rotor vibrate hard, wears out the drive and can cause rotor failure.
Related equipment
Compiled by the AMI Scientific team from standard laboratory practice. Illustrations: AMI Scientific. Updated: 06-11-2026.
Need a centrifuge for your laboratory?
AMI Scientific supplies laboratory glassware, instruments and chemicals with tax invoices and delivery across Indonesia.
Available at AMI Scientific
Sentrifus Mini Joan Lab MC-4/7S
From Rp3.014.000