Answers To Professional Questions Of Ultrafiltration Centrifugal Pipe
1. What is the membrane material of the ultrafiltration tube?
Polyethersulfone membrane has clear and accurate molecular weight interception, stable physical and chemical properties, extremely low protein adsorption and high product recovery
2. If proteins with different molecular weights need to be separated, how much difference does the molecular weight of proteins need?
The two proteins need to be 10 times or more different in size
3. Can ultrafiltration centrifuge tube be used for virus concentration?
Ultrafiltration centrifuge tube can concentrate the virus many times or even high times. We have a special membrane for the virus. Different viruses need to choose the appropriate membrane pore size
4. Can ultrafiltration centrifuge tube be disinfected and alkali resistant?
It can be disinfected with 75% ethanol aqueous solution. Our material can withstand 0.1-0.5n sodium hydroxide alkaline washing
5. Can ultrafiltration centrifuge tube be used for high-pressure sterilization
We have a special ultrafiltration centrifuge tube suitable for high-pressure sterilization
6. Considering the protein stability, can the ultrafiltration tube be centrifuged at low temperature?
Yes, our material is resistant to low temperature, but the concentration time will be longer. The filtration speed of the membrane is related to the feed liquid temperature
7. About the recovery rate
Generally, the recovery rate of solutes with a concentration greater than 0.1mg/ml is 90% or more. Generally, the loss of samples is caused by nonspecific adsorption on the surface of the filter membrane and the surface of the material pipe. In order to obtain a high recovery rate, the retained molecular weight of the selected filter membrane is about 1 / 3 of the target protein, the ultrafiltration membrane is an asymmetric membrane, its pore size is normally distributed, and it may leak under centrifugal high pressure. Under this condition, the protein liquid may be deformed, Therefore, the smaller the interception aperture is, the slower the flow rate is, but the recovery rate will be higher
8. When protein is concentrated, there is precipitation. How to deal with it?
If the protein is concentrated too fast or too much, it may cause protein precipitation. The final concentration after protein concentration should not be too high; For proteins that are sensitive to concentration rate and easy to precipitate, the suggested improvement methods are as follows:
1) Reduce the centrifugal speed,
2) Use ultrafiltration membrane with larger molecular weight
3) Blow and suck the concentration pipe and then centrifuge
9. What are the possible reasons why the ultrafiltration centrifuge tube can not be centrifuged down?
If the ultrafiltration tube cannot be centrifuged, the initial centrifugation can be carried out with about 20% ethanol aqueous solution, because after the ultrafiltration membrane is completely dried, the membrane surface is weakly hydrophobic, and the flux can be restored after soaking with low surface tension solvent
10. Proper use and preservation of ultrafiltration tube
The ultrafiltration tube shall be initially centrifuged with purified water before use to verify its integrity. After each use, it is required to store it in a wet state to prevent the membrane from drying
11. How to remove endotoxin from ultrafiltration tube?
The ultrafiltration tube provided by us has not been treated with endotoxin. At the same time, due to the widespread existence of endotoxins in nature, samples requiring internal toxins can be pre cleaned with 0.5N sodium hydroxide before the experiment, and then cleaned with RO water to remove most of the endotoxin
12. When the concentrated protein is analyzed downstream, it is found that there is interference. What is the reason?
The ultrafiltration tube can be pre cleaned with buffer or purified water. If the interference still exists, clean it with 0.1N sodium hydroxide, and then clean it with purified water
13. There may be nonspecific adsorption between the target protein and the ultrafiltration membrane in the concentration process. How to improve it?
We use hydrophilic polyethersulfone membrane, but for some proteins with special properties, their nonspecific adsorption with the membrane may be enhanced. In this case, we can try to pretreat the ultrafiltration tube before the experiment, or contact our engineer
14. After concentration, it is found that there is no target protein in the concentrate. What are the possible reasons?
1) The initial concentration of protein should not be too low. If the concentration is too low, the membrane may not be retained
2) Select the appropriate membrane pore size. Centrifugation and concentration of ultrafiltration tube belongs to dead end filtration. The membrane pore size is generally less than 2 times or more of the target protein
3) Select appropriate centrifugal speed
4) Whether the target protein precipitates
