English name: centrifugal tube
Definition: Tubular sample container, which can have a sealing cover or a gland, belongs to disposable medical consumables.
Subjects: Mechanical Engineering (first-level subject); laboratory instruments and devices (second-level subject); laboratory centrifuge - laboratory centrifuge parts and accessories (third-level subject)
according to size
A large number of centrifuge tubes (500mL, 250mL)
Ordinary centrifuge tubes (50mL, 25mL, 15mL, 10mL)
Microcentrifuge tubes (2mL, 1.5mL, 0.65mL, 0.2mL, 5mL, 7mL, 0.5mL)
According to the material
Plastic centrifuge tube, glass centrifuge tube, steel centrifuge tube
1. Plastic centrifuge tube
The advantage of the plastic centrifuge tube is that it is transparent or translucent, its hardness is small, and the gradient can be taken out by puncture. The disadvantage is that it is easy to deform, has poor corrosion resistance to organic solvents, and has a short service life.
Plastic centrifuge tubes have tube caps, which are used to prevent sample leakage, especially when used for radioactive or highly corrosive samples. It is very important to prevent sample leakage; the tube cap also has a role to prevent sample volatilization And support the centrifuge tube to prevent deformation of the centrifuge tube. When choosing this point, pay attention to checking whether the tube cover is tight and whether it can be tightly closed during the test, to achieve no leakage when inverted;
We all know that in plastic centrifuge tubes, commonly used materials are polyethylene (PE), polycarbonate (PC), polypropylene (PP), etc. Among them, polypropylene PP tubes have relatively better performance, so we are choosing plastic centrifuge tubes. When possible, consider polypropylene plastic centrifuge tubes.
2. Glass centrifuge tube
When using glass tubes, the centrifugal force should not be too large, and rubber pads are needed to prevent the tubes from breaking. Generally, glass tubes are not used in high-speed centrifuges. The cap of the centrifuge tube is not closed enough, and the liquid cannot be filled up (high-speed centrifuges and angle rotors are used) to prevent overflow and loss of balance. The consequence of spillage is to pollute the rotor and the centrifugal chamber, affecting the normal operation of the sensor. During ultracentrifugation, the centrifuge tube must be filled with liquid, because ultracentrifugation requires a high vacuum, and only filling can prevent the centrifuge tube from deforming.
3. Steel centrifuge tube
The steel centrifuge tube has high strength, no deformation, heat resistance, frost resistance, and chemical corrosion resistance. It is also widely used, but it should also avoid contact with strong corrosive chemicals, such as strong acids and strong alkalis. Try to avoid the corrosion of these chemicals.
The role of the tube cover:
1. When used for radioactive or highly corrosive samples, prevent the samples from leaking out. 2. Prevent the sample from volatilizing. 3. Support the centrifuge tube to prevent deformation of the centrifuge tube.
In biological sciences, especially in the field of biochemistry and molecular biology research, it has been widely used, and each biochemistry and molecular biology laboratory must prepare various types of centrifuges. Centrifugal technology is mainly used for the separation and preparation of various biological samples. The suspension of biological samples is placed in a centrifuge tube under high-speed rotation. Due to the huge centrifugal force, the suspended tiny particles (such as cell organelles, sedimentation of biological macromolecules, etc.) ) settle at a certain speed, thereby being separated from the solution.
When a particle (biological macromolecule or organelle) is subjected to centrifugal force under high-speed rotation, the centrifugal force "F" is defined by the following formula, that is: F = ma = mω2 r a — the acceleration of particle rotation, m — the effective Mass, ω—angular velocity of particle rotation, r—radius of particle rotation (cm). Generally, the centrifugal force is often expressed as a multiple of the earth's gravitational force, so it is called the relative centrifugal force "RCF". Or use the number to multiply "g" to express. For example, 25000×g means that the relative centrifugal force is 25000.