Biochemical Techniques and Instrumentation

4.1.3. Types of centrifuges

There are different types of centrifuges commercially available.

1. Microfuges

They are used to centrifuge small volume of samples in Eppendorf tubes. The modern refrigerated microfuges are equipped with adaptors to accommodate standardized microtubes of 0.5 to 1.5 ml volumes and they provide centrifugal fields of up to 30,000g.

2. Simple bench top centrifuges

They are mainly used to collect small amounts of biological materials such as blood.

3. Larger preparative bench top centrifuges

They are used to spin various types of containers, which include 5 to 250 ml plastic tubes or 96 well ELISA plates. They develop a maximum centrifugal fields of 3000 to 7000g.

4. High speed refrigerated centrifuges

They are employed to prevent denaturation of sensitive protein samples during centrifugation. They are used to sediment large intact organelles, cellular debris and microorganisms. They differentially separate nuclei, mitochondria or chloroplasts of the cell, and operate at maximum centrifugal fields of 1,00,000g.

5. Ultracentrifuges

They are employed to sediment smaller microsomal vesicles or ribosomes and operate at a centrifugal fields of 3,00,000 g.

The classification of centrifuges based on the speed of rotation into low speed, high speed and ultra speed centrifuges is given in Table 4.1