Centrifuges are divided into industrial centrifuges and laboratory centrifuges by application. The latter is divided into preparative centrifuges and analytical centrifuges according to their functions. Preparative centrifuges are generally used to separate a variety of biological materials, and the amount of separated samples is relatively large. It is also the type of centrifuge equipped in most scientific research laboratories. Analytical centrifuges are often used to study the physical and chemical properties of pure biological macromolecules and particles. Generally, there are optical systems that can monitor the behavior of particles in a centrifugal field, can infer the purity, shape and molecular weight of substances, and are all ultracentrifuges. . Here are some preparative centrifuges commonly used in laboratories.
Preparative centrifuges can be divided into ordinary centrifuges, high-speed centrifuges, ultra-centrifuges and so on according to the rotation speed. details as follows:
1. Ordinary centrifuge (room temperature centrifuge)
The large speed is less than about 10,000 rpm, and the capacity is tens of milliliters to several liters. The separation form is solid-liquid sedimentation. The speed cannot be strictly controlled. It usually does not have a refrigeration system and operates at room temperature. : Cells and so on. It is often seen in cell culture laboratories.
2. High-speed centrifuge (including high-speed refrigerated centrifuge and normal-temperature high-speed centrifuge)
The rotation speed is 10000-30000rpm. Generally, there is a refrigeration system to eliminate the heat generated by the friction between the high-speed rotating rotor and the air. The temperature of the centrifugal chamber can be adjusted and maintained at 0 ℃ -4 ℃, and the speed and temperature can be controlled strictly and accurately. And time, and have a pointer or digital display. It is usually used for the separation and purification of microbial cells, cell debris, large organelles, ammonium sulfate precipitation and immunoprecipitates, but it cannot effectively settle viruses, small organelles or single molecules. High-speed centrifuges are common types of centrifuges in laboratories, and are usually equipped in molecular laboratories.
The rotation speed can reach more than 30,000 rpm, the centrifugal capacity is from tens of milliliters to 2 liters, and the separation form is differential sedimentation separation and density gradient zone separation, which must be strictly balanced (error <0.1g). The main difference from the high-speed centrifuge is the addition of a vacuum system. Commonly used for the isolation of subcellular organelles, viruses, nucleic acids, proteins and polysaccharides. Ultracentrifuges are expensive.
4. Centrifuges can be divided according to their placement methods: vertical centrifuges (also called floor centrifuges) and desktop centrifuges (also called desktop centrifuges)