Definition and Principle
1. Definition: A centrifuge is a method of separating, concentrating and purifying biological samples by using the centrifugal force of rotation and the difference in sedimentation coefficient or buoyancy density of the substance.
2. Principle: The working principle of a centrifuge is mainly based on two effects: centrifugal filtration and centrifugal sedimentation. Centrifugal filtration is the centrifugal pressure generated by a suspension in a centrifugal field, which acts on the filter medium, so that the liquid passing through the filter medium is called filtrate, and the solid particles are retained on the surface of the filter medium, thereby achieving solid-liquid separation. Centrifugal sedimentation uses the principle that the components of a turbid liquid (or emulsion) with different densities quickly settle and stratify in a centrifugal field to achieve liquid-solid (or liquid-liquid) separation.
Types and classifications
1. Classification by speed
Low-speed medical centrifuge: generally refers to centrifuges with a speed of less than 10,000 rpm.
High-speed medical centrifuge: generally refers to centrifuges with a speed of 10,000 to 30,000 rpm.
Ultra-high-speed medical centrifuge: generally refers to centrifuges with a speed greater than 30,000 rpm.
2. Classification by rotor type
Horizontal rotor or bucket medical centrifuge.
Fixed-angle rotor or angle rotor medical centrifuge.
3. Classification by use and function:
Blood centrifuge: used to separate formed elements in blood.
Blood type card centrifuge: specifically used for centrifugal processing of blood type detection cards.
Urine sediment centrifuge: used for urine sediment examination.
Capillary centrifuge: suitable for centrifugation of samples in capillaries.
Cell centrifuge: used for cell separation and purification.
Biopharmaceutical centrifuge: used for material separation in the biopharmaceutical field.
Gel bubble processing centrifuge: specifically used for gel and bubble processing.
Application Fields
Centrifuges have a wide range of applications, including but not limited to dehydration, clarification, concentration, classification and separation. In medical examinations, centrifuges are often used to separate serum, plasma, precipitate proteins or perform urine sediment examinations. In industrial production, centrifuges are used to separate and purify various materials.
Usage steps and precautions
1. Usage steps:
Place the centrifuge on a flat table and make sure it is stable. Open the door cover, check and fix the centrifuge rotor, and then put in the centrifuge tube.
Close the centrifuge cover (some centrifuges may not have it) and the door cover, plug in the power supply, set the speed and other parameters, and then start the centrifuge. When the centrifugation is completed, the machine will sound a reminder. At this time, you can take out the centrifuge tube and turn off the power supply.
2. Notes:
Choose the appropriate centrifuge model and speed according to the experimental requirements. Before operation, make sure the rotor of the centrifuge is clean and perform necessary disinfection and cleaning.
Check the shelf life of the centrifuge tube and the condition of the tube wall before use to avoid using cracked or expired centrifuge tubes.
When loading samples into the centrifuge, make sure that the lid of the sample tube or centrifuge tube is firmly closed to prevent sample leakage or splashing.
Pay attention to the balance of the sample. Generally, equal amounts of samples are placed diagonally for balance. During operation, strictly follow the instructions for use of the centrifuge and follow safety regulations.
After use, clean the centrifuge in time to keep the equipment clean and in normal operation.
Maintenance and care
In order to ensure the normal operation of the centrifuge and extend its service life, it needs to be regularly maintained and cared for. This includes cleaning the outside and inside of the centrifuge, checking and replacing worn parts, and regular lubrication. In addition, attention should also be paid to the storage environment of the centrifuge to avoid adverse effects such as humidity and high temperature.
As an important separation machine, centrifuge is widely used in various fields. Understanding the definition, principle, type, application field, use steps and precautions of centrifuge will help you better use and maintain the centrifuge.