Types and Characteristics of Centrifuges

Laboratory centrifuges are useful devices, thus are frequently used in many types of clinical and research trials.

Centrifuges have different types that accommodate different types of centrifugation, including preparative and analytical centrifugations. The first one aims to separate certain particles, whereas the second one estimates physical properties, such as sedimentation rate or molecular weight (Sapkota, 2021).

When choosing a 50ml centrifuge tube, two of the most crucial factors are the clinical method and the laboratory size. Some centrifuges are used for various applications, while others are used for specific purposes.

Their operation is always the same, even though there are many types of centrifuges. The basic function of centrifuges is to rotate the samples around an immovable angle and isolate fluids from a sample of solid substance. The sedimentation principle is applied to do this process. Sedimentation refers to the sediments’ deposition. It occurs when the suspension’s particles settle beyond the fluid in which they are entrained and come to rest against a barrier.

Types of Centrifuge

In laboratories, you may find three types of centrifuges: large ones, benchtop centrifuges, and mini-centrifuges.

Large centrifuges and benchtop centrifuges are usually known as “centrifuges”, whereas smaller centrifuges are mini or microcentrifuges. These mini centrifuges use plastic tubes with 5ml and 10ml capacities called “microtomes” (Sapkota, 2021). These are used to handle minute amounts of sample liquids.

Benchtop centrifuges have two prominent features: They are user-friendly and provide more versatile centrifugation solutions. Even though they were originally designed to be used in laboratories with limited space, they are currently used in research, development, and test laboratories.

Typically, the largest centrifuges are usually have a big size. They have two types: high-speed centrifuges and ultracentrifuges, which are distinguished into analytical and preparative.

Benchtop Centrifuges

Benchtop centrifuges are also called clinical, medical, or low-speed centrifuges. They are small in size and do not have refrigeration. They reach maximum speeds of 4000-5000 rpm. They are used to separate large particles, such as cells, in operations, including the concentration of cell suspensions, separation of serum or plasma, and others. The standard tube is 16×100 mm or 15 mL capacity, with a curved or conical bottom. (Sapkota, 2021)

Mini Centrifuges

They are a variation of benchtop centrifuges. However, these centrifuges can achieve a speed of 10,000 rpm or more. One of the most common uses of these centrifuges is in the molecular biology field. They use microtubes with 0.2 mL, 0.5 mL, or 1.5 mL capacity. (Sapkota, 2021)

High-Speed Centrifuges

They reach at least 18,000 and a maximum of 25,000 rpm. They usually have vacuum systems that prevent the rotor from heat due to friction with the air. A rotor in the high-speed centrifuge is its rotating unit with fixed holes drilled at an angle. The vacuum system allows these centrifuges to control the temperature more precisely than those without this system. (Sapkota, 2021)

Although high-speed centrifuges are insufficient in separating ribosomes, viruses, and macromolecules, they effectively separate cell fractions. With a refrigeration system, such as condensers and compressors, these centrifuges allow samples to be kept below the ambient temperature of any object or environment.

Ultracentrifuges

They exceed 50,000 rpm. Therefore, they operate with an auxiliary system to keep the motor and the rotor chamber (where the samples are) cool. By achieving a high vacuum level, they can generate 600,000 g, enough to separate small proteins. Ultracentrifuges are divided between analytical and preparative ultracentrifuges. (Sapkota, 2021)

The most noticeable difference between them is that the analytics are based on an optical system visualizing the sample’s sedimentation in real-time. Thus, this sedimentation process assists in obtaining accurate data on sedimentation properties (sedimentation coefficients, molecular weights). On the other hand, preparative ultracentrifuges are responsible for purifying the samples for later use, which is done by separating particles with viruses and macromolecules with low sedimentation coefficients.

Understanding the different characteristics of different types of centrifuges and their applications is inevitable to select the right one. We are the best choice for molecular biology products.  With Molecular Biology Products’ products, you can perform all laboratory tests and experiments. Prefer our products and perform what you need!

References

Sapkota, A. (2021). Types of Centrifuge and Centrifugation (definition, principle, uses). microbenotes.com. Retrieved 7 February 2022, from https://microbenotes.com/centrifuge-and-centrifugation/.