Centrifuge rotor types: fixed-angle vs swing-bucket

The rotor determines how samples experience centrifugal force and what separations are possible.

Fixed-angle rotors

Tubes are held at a set angle (often 25–45°). Pellets form on the tube wall/bottom. Best for fast pelleting of cells and precipitates, and for high-speed work.

Swing-bucket rotors

Buckets swing horizontal during the run, so the pellet forms flat at the tube bottom. Essential for density-gradient separations and clean band recovery.

Choosing

• Routine pelleting → fixed-angle.
• Gradients, blood components, sensitive bands → swing-bucket.
• Always confirm the rotor is rated for the required RCF (g-force), not just RPM.