Centrifugal Filters

Centrifugal Filters



· Rapid protein concentration--- 25 to 80-fold concentration.

· Quick processing time---The general concentration time is 10-30 minutes.

· High recovery rate--->90%.

· Low protein adsorption---The RC membrane have extremely low protein adsorption.

· A variety of MWCO---3K, 10K, 30K and 100K available.

Protein recovery rate of cobetter centrifugal filter



· Concentration and purification of proteins such as antigens, antibodies, enzymes and biological samples such as nucleic acids and microorganisms.

· Protein desalting, buffer exchange. Biomolecules are isolated from tissue culture fluids or cell lysates.

· Remove primers, linkers or molecular markers from the reaction mixture.


How to choose Cobetter Centrifugal Filters?

To choose which type to use, determine the molecular weight (MW) of your macromolecule of interest, and select an ultrafiltration membrane with a molecular weight cut-off (MWCO) that is 2-3 times smaller than the MW of your macromolecule.

How to choose Cobetter ultrfiltration centrifugal filter

Then add your sample to the filter, taking care not to overfill the device. Typically, samples should not exceed 2/3 of the filter's maximum volume capacity. 


Centrifugal Filter Units Structure & Adapted Equipment

Cobetter Briscale® ultrafiltration centrifugal filter units consist of a lid, a filter unit, and a centrifuge tube.

It requires a rotor or rotor adapter compatible with 15mL (for 4mL centrifugal filter) or 50mL (for 15mL centrifugal filter) conical bottom centrifuge tubes. Both the swinging bucket rotor and the fixed-angle rotor must meet this requirement.

Cobetter ultrfiltration centrifugal filter structure


How to use Cobetter centrifugal filter devices?

Rinse Before Use

  1. The ultrafiltration centrifugal filter may contain a small amount of glycerol. To avoid interference, it is recommended to rinse before use.
  2. Add 4mL pure water, deionized water or buffer solution to the ultrafiltration device, centrifuge at 4000xg(swing bucket)/ 5000xg(fixed angle 45°) for 5-10 min, and pour out all liquids in the ultrafiltration unit and centrifuge tubes.
  3. If interference persists, wash with 0.1N NaOH under the above conditions, then rinse 2-3 times with ultra-pure water, deionized water, or buffer.
  4. Once the ultrafiltration membrane is wet, it needs to be kept wet until it is used up.

Note: 100 kDa ultrafiltration centrifugal filter devices can be used at a maximum of 3000xg in a swinging bucket or at a fixed angle.

Related Articles:

How to Use Centrifugal Filter Units?

How to Choose MWCO Filters?

How to Select the Correct MWCO for DNA, RNA and Protein Purification and Concentration


  • Cobetter_Centrifugal_Filters_Brochure_202404 Download

Q: How to select a centrifugal filter?

A: First, determine the starting volume of your sample.

Second, determine the molecular weight (MW) of your macromolecule, then choose a centrifugal filter with a MWCO that is 2-3 times smaller than the MW of your macromolecule.

Q: Are Cobetter centrifuge filters reusable?

A: We recommend using them once, but some of our customers tried to use it for the same sample up to maximum 3 times, only for reference.

Q: How to clean Cobetter centrifuge filters?

A: First, soak them in 0.1M NaOH for 24 hours, then soak them in 20% ethanol for preservation.

Q: Can Cobetter centrifuge filters cut off 40,000 MW of pvp or 20-100nm nanosilver? If 20-100 nm nanosilver contains 40,000 MW pvp at the same time, can they be cut off at the same time?

A: You can choose 10kDa, and they can be cut off at the same time.

Q: Liposomes, want to be used to separate the free drug (MW 1550D), and the system solvent is PBS buffer.

A: Cobetter centrifuge filters are compatible, but we are not sure if the 5000xg centrifugal force will destroy the liposomes as we haven't tested it.

Q: There are two viruses that need to be concentrated, one with a diameter of 150nm~200nm and the other with a diameter of 40nm, which size of centrifuge filter is recommended?

A: You can choose 30kDa or 100kDa centrifuge filters.

Q: Which centrifuge filters are suitable for 100nm liposomes, or LNP? Will the recovery rate be low?

A: Use 100kDa centrifuge filters below 2,000 rpm. If the recovery rate is low please test the downstream filtrate to see if it's leaking through. 100kDa centrifuge filters shouldn't leak, so if a leak happens it's more likely due to excessive shear.

Q: Can Cobetter centrifuge filters be used to filtrate exosomes?

A: Yes, and it is recommended to use 100kDa first and then 3kDa centrifuge filters to concentrate exosomes with serum, and 3kDa centrifuge filters can be used directly for those without serum.

Q: What is the volume after concentration by 4ml centrifuge filters?

A: 80-200μL.

Q: What does KDa/Da mean?

A: KDa/Da is the molecular weight unit of proteins in biology.

Q: What's the material of the built-in ultrafiltration membrane?

A: Cobetter centrifugal filters are made with Regenerated Cellulose ultrafiltration membranes.

Q: What is the centrifuge time and speed for concentration to 100x?

A: Add 12mL solution upstream as an example, centrifuge at 3000~5000rpm until the upstream liquid remaining below the 250μL scale. Based on the feedback of our customers, centrifuge around 10~20 minutes, which is related to the concentration of the antigen.

Q: Do Cobetter centrifuge filters come with instructions?

A: Instruction manual is supplied with products.

Q: What is the size of the outer tubes?

A: The outer tubes for 4ml centrifuge filter is 15ml, and the outer tubes for 15ml centrifuge filter is 50ml.

Q: Is it possible to make liquid pass through the membrane by filtration rather than centrifugation?

A: No, it isn't. Cobetter centrifuge filters are compatible with centrifuges.

Q: Are Cobetter centrifuge filters compatible with regular centrifuges?

A: No, they aren't. They are matched to conical bottom centrifuges.

Q: Resistance of Cobetter centrifuge filter membrane.

A: You can check the chemical compatibility sheet in the product brochure which can be downloaded in the Documents Tab.