Buying guide
How to Choose a Laboratory Centrifuge: RCF, Rotors, Cooling and Capacity
Short answer
Choose a laboratory centrifuge by four things: the g-force (RCF) your protocol asks for, the tube sizes and how many you spin per run, whether samples must stay cold, and the rotor type. Microcentrifuges handle 1.5 to 2 mL tubes at high speed, benchtop models take 15 and 50 mL tubes and blood tubes, and floor-standing models are for large volumes.
Start from RCF, not RPM
Protocols give centrifugation in relative centrifugal force (RCF, ×g) because the same speed produces a different force in rotors of different radius. Convert with:
RCF = 1.118 × 10-5 × r × rpm2
where r is the radius from the rotor axis to the bottom of the tube, in centimetres. A rotor with a 10 cm radius at 10,000 rpm gives about 11,180 ×g. Check that the model reaches the RCF you need with the rotor you will actually use.
Micro, benchtop or floor-standing
| Type | Typical tubes | Used for |
|---|---|---|
| Microcentrifuge | 0.2 to 2 mL | DNA and protein work, spin columns, quick pelleting |
| Benchtop | 15 and 50 mL conical, blood tubes, plates | Clinical and QC labs, cell work, general sample preparation |
| Floor-standing | Large bottles and high tube counts | Production, blood banks, high throughput |
On this site, Hanil Scientific models range from the M15R micro centrifuge at 15,000 rpm to the S12R at 12,000 rpm and the T05R at 5,000 rpm for larger loads.
Fixed-angle or swing-out rotor
- Fixed-angle rotors hold tubes at a set angle. They reach higher speeds and pellet faster; they are the usual choice for microtubes and high-speed work.
- Swing-out (swing-bucket) rotors let tubes swing horizontal. The pellet forms flat at the bottom and layers separate cleanly, which suits blood separation, density gradients and large tube counts at lower speeds.
Many labs buy one centrifuge with two rotors rather than two machines.
Refrigerated or ambient
Spinning heats the rotor through air friction. If you work with proteins, nucleic acids, enzymes or live cells, a refrigerated centrifuge that holds around 4 °C protects the sample. For routine separations at room temperature, an ambient model costs less and needs less bench space.
Safety and running costs
- Balance tubes by mass, opposite each other, every run. Choose a model with lid lock and imbalance detection.
- For potentially infectious samples, use sealed rotors or safety cups and open them in a biological safety cabinet, as the WHO Laboratory Biosafety Manual advises.
- Ask about rotor life, spare adapters and who services the unit locally.
Concentrating DNA and RNA samples
A vacuum concentrator (often called a DNA concentrator or speed-vac) combines centrifugation with vacuum and gentle heat to evaporate solvent from many small samples at once, without cross-contamination. It is a separate instrument from a standard centrifuge; Tiba Scientific supplies both.
Checklist before you request a quotation
- Maximum RCF your protocols need, with the rotor radius.
- Tube or plate formats, and the number per run.
- Temperature range, if samples must stay cold.
- Rotor types: fixed-angle, swing-out, or both.
- Biosafety needs: sealed rotors or aerosol-tight buckets.
- Bench space, power supply and noise limits.
- Installation, training and maintenance in Egypt.