Laboratory centrifuge basics

Laboratory centrifuge basics

Posted by ShopLaboratory on 23rd Feb 2022

Laboratory centrifuge basics

Centrifuges are versatile tools used in various research, clinical, and industrial applications. They enable the separation of different components, such as cells, proteins, DNA, RNA, and organelles, based on their density and size. By subjecting the mixture to high centrifugal forces, denser particles migrate towards the bottom of the sample tube, forming a pellet, while less dense substances remain in the supernatant.

The working principle of laboratory centrifuge

A centrifuge is a laboratory device that separates components of a mixture based on their density using centrifugal force. By the principle of sedimentation, high-speed rotation creates the centrifugal force, which allows materials of different densities to be separated. When the rotor spins rapidly, it generates a centrifugal force that is much greater than the force of gravity. This centrifugal force pushes the denser components of the mixture towards the outer edges of the rotating container, while the less dense components remain closer to the center. As a result of this separation, the denser particles or substances form a pellet or sediment at the bottom of the container, while the less dense substances form a supernatant or a liquid layer above the sediment. The speed and duration of the centrifugation process depend on the nature of the mixture and the desired level of separation.

The principle centrifugal force

Centrifugal force is a perceived force that appears to act on an object moving in a curved path or rotating around a central point. It is an apparent or fictitious force, as it does not arise from any physical interaction but rather from the inertia of the object. Centrifugal force can be calculated using the following formula: Centrifugal force = (mass x radial distance x angular velocity²) where mass is the mass of the object radial, distance is the distance from the center of rotation to the object, angular velocity is the rate at which the object is rotating, expressed in radians per second.

The unit of centrifugal force is usually Newtons (N) or pounds-force (lbf). In practical terms, when measuring the centrifugal force in a centrifuge, it is common to express it in terms of relative centrifugal force (RCF) or gravitational force (g-force). These terms are used to describe the effective acceleration experienced by particles or substances due to centrifugation. The RCF or g-force can be calculated using the following formula: RCF = (1.12 x 10^-5) x (r x N)² where RCF is the relative centrifugal force or g-force, r is the radius from the center of rotation to the sample, in centimeters, N is the rotational speed of the centrifuge, in revolutions per minute (rpm).

In practical laboratory settings, centrifugal force or RCF can be measured using specialized instruments called tachometers or centrifuge speedometers. These instruments are designed to measure the rotational speed of the centrifuge accurately, allowing the calculation or direct display of the corresponding centrifugal force or g-force.

Centrifuge applications in laboratory

Centrifuges may be used in cases when the separation of liquid or gas components is necessary. The separation of components is an important part during diagnostics and analysis, for example, in blood testing – separating blood plasma from red blood cells and platelets. All in all, centrifuges are used for the purification of components of cells, viruses, proteins, and other substances.

  • the functionality of temperature control (ventilated, cooled, cooled and heated, etc.)
  • material (plastic, metal, glass),
  • dimensions
  • number of tubes
  • capacity
  • custom features you may need.

Types of centrifuges

There are several types of laboratory centrifuges, each designed for specific applications and separation needs. Here are some common types of laboratory centrifuges:

  • Microcentrifuge: This type of centrifuge is used for small sample volumes, typically ranging from microliters to a few milliliters. Microcentrifuges have high rotational speeds and are often used in molecular biology, biochemistry, and microbiology research.
  • Ultracentrifuge: Ultracentrifuges are high-speed centrifuges capable of reaching extremely high rotational speeds, often in the range of 60,000 to 150,000 revolutions per minute (rpm). They are used for applications that require very fine separation of particles, such as isolating subcellular components and studying macromolecules like proteins and nucleic acids.
  • Refrigerated Centrifuge: This type of centrifuge includes a temperature control system, usually a refrigeration unit, to maintain a cool environment during centrifugation. It is used for applications that require low temperatures, such as preserving the integrity of heat-sensitive samples or working with enzymes and proteins that may be affected by higher temperatures.
  • High-Speed Centrifuge: High-speed centrifuges are designed to achieve fast acceleration and deceleration rates, allowing for quick separation of samples. They are commonly used in clinical laboratories for applications such as blood component separation and medical diagnostics.
  • Benchtop Centrifuge: Benchtop centrifuges are compact centrifuges suitable for use on laboratory benches or in small spaces. They are versatile and can handle a range of sample volumes and applications, making them widely used in various research and clinical settings.
  • Floor-Standing Centrifuge: These are large, heavy-duty centrifuges used for industrial and large-scale applications. They have a high capacity and can handle large volumes of samples, making them suitable for bioprocessing, pharmaceutical production, and other industrial processes.
  • Preparative Centrifuge: Preparative centrifuges are specifically designed for large-scale sample separation. They are capable of handling significant sample volumes and are often used in biotechnology and pharmaceutical industries for purifying and isolating compounds on a large scale.

These are just a few examples of laboratory centrifuges, and there are other specialized types available for specific applications. The choice of centrifuge depends on factors such as sample volume, required speed and acceleration, temperature control needs, and the specific separation goals of the experiment or process.

Finally, if you want to be sure of making the right decision while choosing a centrifuge, the best way to do it is to talk to a professional. If you want to consult with a specialist, we recommend writing to our competent support staff at