How to choose ordinary centrifuge in laboratory

The centrifuge is one of the most commonly used basic equipment in the laboratory. It is widely used in hospital laboratories. The centrifuge is an indispensable tool for separating serum, sedimenting visible cells, concentrating bacteria, and PCR tests.
Choose an ordinary centrifuge, according to the size of the workload, mainly from two aspects of speed and capacity. The following is a detailed introduction to the issues that should be paid attention to when choosing a precision centrifuge:

1 Rotation speed: Centrifuges are divided into low-speed centrifuges <10000 rpm / min, high-speed centrifuges 1 0000 rpm / min to 30000 rpm / min, ultra-high-speed centrifuges> 30000 rpm / min, each centrifuge has Rated maximum speed, the maximum speed refers to the speed under no-load conditions, but the maximum speed varies according to the type of rotor and the size of the sample mass. For example, the rated speed of a centrifuge is 16000 rpm / min, indicating that the rotor rotates 16,000 times per minute when no-load. After adding the sample, the speed will definitely be less than 16000 rpm / min. Different rotors have different maximum speeds. Imported centrifuges can be equipped with multiple rotors. A few domestic centrifuges have successfully developed such technologies, such as TG16 desktop high-speed centrifuge, TGL16, TGL20 desktop high-speed refrigerated centrifuge, etc. Many models can be equipped with 16 kinds of rotors, which can be used for one machine. , The horizontal rotor can reach 15000 rpm / min, but the angle rotor can reach about 14000 rpm / min, the specific difference should consult the product sales staff and the relevant technical personnel of the production plant in detail, so the speed selection should be careful, the choice The maximum speed of the centrifuge is higher than the target speed. For example, if the target speed is 16000 rpm / mIn, the maximum speed of the selected centrifuge must be higher than 16000 rpm / min. Generally, the separation effect mainly depends on the rotational speed, but the centrifugal force, so sometimes the rotational speed does not meet the requirements, as long as the centrifugal force can reach the standard, the experiment can achieve the effect you need. Calculation formula of centrifugal force: RCF = 11.2 × R × r / min / 10002 R stands for centrifugal radius and r / min stands for speed.

2Temperature: Some samples such as proteins and cells will be destroyed in high temperature environment. This requires the selection of a refrigerated centrifuge, which has a rated temperature range. The heat generated by the centrifuge at high speed and the balance of the centrifuge's refrigeration system are at a certain temperature. Generally, the frozen centrifugal sample needs to be maintained at 3 ℃ ~ 8 ℃. The specific amount can also depend on the rotor, such as the rated temperature of a centrifuge The range is -10 ℃ ～ 60 ℃. When the horizontal rotor is installed, it can reach about 3 ℃. If it is an angle rotor, it may only reach about 7 ℃. This point also requires detailed consultation with the product sales staff and the relevant technical personnel of the production plant.

3 Capacity: How many sample tubes need to be centrifuged each time 7 How much capacity does each sample tube need? These factors determine the total capacity of a centrifuge. In simple terms, the total capacity of the centrifuge = the capacity of each centrifuge tube × the number of centrifuge tubes Number, total capacity and workload size are matched.

4 Rotor: The rotor of the centrifuge is mainly divided into two types. The horizontal rotor: the hanging blue is in a horizontal state during operation and is at a right angle to the rotating shaft, and the sample concentrates the sediment at the bottom of the centrifuge tube: the angular rotor: the centrifugal container and the rotating shaft form a fixed angle The sample concentrates the precipitate on the bottom of the centrifuge tube and the side wall near the bottom. If you want to concentrate the separated sample on the bottom of the centrifuge tube, choose a horizontal rotor. If you want to concentrate the sample on the bottom of the centrifuge tube and the side wall near the bottom, choose an angle rotor.

There are some special tests or special samples that require special rotors such as: large-capacity hanging baskets are mostly used in blood stations, microplate rotors, slide rotors, PCR rotors, test tube rack rotors and capillary rotors. The rotor has a fixed specification, which is combined with the capacity of the centrifuge. For example, a 36 × 5 ml angular rotor determines both the type of rotor and the capacity of the centrifuge, so the choice of rotor is very important.

5 Control system: High-end centrifuges use microcomputer control systems. These control systems can not only ensure the safe operation of the centrifuge but also automatically complete the work tasks. Many centrifuges now have better user-friendly control systems. For example: rotor identification function, safety lock function, fault prompt function, acceleration and deceleration curve and so on. In addition to the above points, we must pay attention to some details and necessary accessories. The main component of the centrifuge is a motor. The motor is divided into a carbon brush motor and a carbon brushless motor. The former has been eliminated. Most of the current centrifuges are carbon brushless motors, and some motors also have a brake function. Refrigerated centrifuges also have differences in refrigeration, and the current environmentally friendly technology is of course fluorine-free refrigeration. In addition to this, the noise problem must be considered, and the centrifuge with less noise should be selected as much as possible, so as to maintain a comfortable experimental environment. Care should also be taken in terms of accessories. Some experiments use special centrifuge tubes to centrifuge toxic samples or samples that require ultra-high-speed centrifugation. Such a centrifuge tube must be equipped with a corresponding tube sleeve to be safer. There are also special sample containers with irregular sample bottles, blood bags, etc. These details and accessories must be considered carefully when selecting a centrifuge, otherwise normal work cannot be performed.