Amicon Ultra Centrifugal Filters Alternatives | VWR Centrifugal Filters

Keep your workflow moving when Amicon Ultra (UFC) devices aren’t available. Use the volume (0.5/4/15 mL) and MWCO (3–100 kDa) matrix below to find a like-for-like VWR alternative, then jump straight to a pre-selected variant for a quick quote.

Typical applications include protein concentration, desalination, and buffer displacement. It can also be used for nucleic acid primer removal, plasmid purification and collection, exosome enrichment, and other applications.
PES membrane is an ideal membrane material for the processing of biomacromolecule samples, with low adsorption and good chemical compatibility.

• Manufacturing process certified to ISO 9001;
• Fast filtration flow rate and high sample recovery rate;
• Low binding rate of biomolecules, high chemical compatibility;
• Anti filter dry lock design to avoid sample damage caused by excessive centrifugation;
• Multiple pore size specifications to meet different molecular weight cutoff requirements;
• 100% integrity tested.

Specifications：

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Instructions:

Pre cleaning:

The PES membrane of this ultrafiltration tube contains trace amounts of glycerol and  protective  agents.  To  avoid  interference  with  analysis,  the  filter  can  be centrifuged with deionized water or buffer solution before use and repeated 1-2 times to remove interference. Attention: Once the filter is wet, it should be kept moist until it is used up.

Instructions for using 4ml and 15ml ultrafiltration tubes:

1. Remove the lid and transfer the sample into a filter (4ml ultrafiltration tube not exceeding 4.5ml, 15ml ultrafiltration tube not exceeding 15ml), and cover with a lid to prevent evaporation during centrifugation.
2. Place the filter into a centrifuge that can hold 15/50ml conical tubes. Always use another centrifugal filter containing an equal volume of sample to balance the rotor.
3. The time required to rotate the equipment with the recommended force. Rotate the 4ml ultrafiltration tube at a speed of 1000 to 6000 xg, usually for 10 to 60 minutes, to achieve the desired concentration volume; A 15ml ultrafiltration tube is rotated at a speed of 1000 to 5000 xg, typically for 10 to 60 minutes, to achieve the  desired  concentration  volume. Suggest  determining  the  rotation  time  and gravity for each application.
4. To  recover  the  concentrated  solute,  insert  a  pipette  at  the  bottom  of  the filtration  device  and  shake  it  left  and  right  to  extract  the  sample  to  ensure complete  recovery.  The  filtered  liquid  can  be  stored  in  a  centrifuge  tube. Explanation: To  achieve  ideal  recovery,  please  take  the  concentrated  sample
   immediately after centrifugation.

Instructions for using 0.5ml ultrafiltration tube:

1. Remove the lid and transfer no more than 0.5 mL of the sample into the filter. Cover the lid to prevent evaporation of the solution during centrifugation.
2. Place the ultrafiltration tube into a centrifuge that can hold 1.5 mL or 2.0 mL centrifuge tubes. Centrifuge at a centrifugal force not exceeding 14000g for 10 to 30 minutes to achieve the desired concentration volume. It is recommended to determine the appropriate centrifugation time and force for each application through  pre  experiments.  Attention:  Please  pay  attention  to  balancing  the centrifuge during centrifugation!
3. To  recover  the  concentrated  solution,  invert  the  filter  in  another  clean centrifuge tube, place it in the centrifuge, align the open cover with the center of the  rotor,  and  pay  attention  to  balancing.  Centrifuge  at  a  centrifugal  force  of 1000g for 1 to 2 minutes to transfer the concentrated solution from the filter to the  centrifuge  tube.  Both  filtrate  and  concentrate  can  be  stored  in  centrifuge tubes.

Schematic diagram for centrifugal use of 0.5ml ultrafiltration tube

Non specific adsorption:

PES  membranes have  low  biomolecule  binding  properties  and  excellent biological and chemical tolerance. However, when purifying proteins at the microgram or nanogram level, special attention still needs to be paid to the adsorption  of  equipment  components.  Even  if  the  material  used  in  this ultrafiltration tube is low adsorption plastic, adsorption may still occur when concentrating or separating high "viscosity" proteins and biomolecules. Preprocessing filters can further reduce non-specific adsorption of the filter.

The specific operation is as follows:

1. Fill the filter with 10% glycerol.
2. Soak overnight at room temperature.
3. Fill the filter with deionized water, let it stand for 1 to 2 minutes, and discard the liquid in the tube. Repeat this process 1 to 2 times.
4. Fill the filter with deionized water and centrifuge to allow the deionized water to pass through the filter membrane, repeating 1 to 2 times.

Desalination or filtration:

1. Concentrate  the  sample  at  least  tenfold  using  a  centrifugal  filter  (e.g. concentrate 15mL to 1.5 ml).
2. Dissolve in exchange buffer and centrifuge again to concentrate tenfold.
3. Repeat  this  procedure  3  to  5  times  to  remove  95  to  99%  of  salt  or buffer solution.

Precautions:

1. The ultrafiltration tube product is an unsterilized disposable product. If any damage is found, please do not use it.
2. Super tube products are only for scientific research use and are not intended
   for in vitro diagnostics.

Ultrafiltration tube FAQ：

Q: How to choose the appropriate ultrafiltration tube?

A: Select the size of the ultrafiltration tube that is similar in volume to the sample being processed; The general principle for selecting the cut-off molecular weight is to choose an ultrafiltration membrane with a cut-off molecular weight three times  smaller  than  that  of  the  target  substance.  However,  considering  the differences in biological samples themselves, pre-experimental verification can select the ultrafiltration tube that is most suitable for processing the biological sample (the table below is a commonly used membrane selection guide). 

Membrane selection guidance (recommended molecular weight cut-off)

Q: Are there any requirements for the centrifuge rotor model during the use of ultrafiltration tubes?

A: 4ml and 15ml ultrafiltration tubes need to be used with centrifuge rotors that accept standard 15ml and 50mL conical tubes, because the bottom of the outer tube of our 4ml and 15ml ultrafiltration tubes is conical. If the centrifuge rotor is not matched, it can easily cause uneven force on the bottom and pose a risk of deformation.

Q: Are there any requirements for the centrifugal speed during the use of ultrafiltration tubes?

A: Different models of ultrafiltration tubes have corresponding maximum
centrifugal force limits. Using them beyond the maximum centrifugal force may pose a significant risk of liquid leakage, which needs to be confirmed before use.

Conversion table of centrifugal force and rotational speed

Q: How can ultrafiltration tubes be disinfected and sterilized?

A: The ultrafiltration tube is compatible with 70% ethanol and can be sterilized by soaking and centrifuging the components of the ultrafiltration tube in 70% ethanol. However, we recommend using a sterilization needle filter to filter and sterilize the samples processed by the ultrafiltration tube to ensure their sterility.

Q: What is the difference in size between two proteins separated by ultrafiltration tubes?

A: Based on experience, it is recommended that the molecular weights of two
proteins differ by at least one order of magnitude (10 times).

Q: Can ultrafiltration tubes be used for virus concentration?

A: Sure. Select the appropriate ultrafiltration tube with molecular weight cut-off based on the shape and size of the virus (which can be confirmed through preliminary experiments).

Q: Can ultrafiltration tubes be used for high-pressure sterilization?

A: Ultrafiltration tubes cannot be used for high-pressure and high-temperature sterilization.

Q: Does the ultrafiltration tube not contain RNAse?

A: We cannot guarantee that the ultrafiltration tube does not contain RNAse. It is recommended to soak it in 0.1% DEPC at 37 ℃ for 2 hours to completely inactivate RNAse; Residual DEPC can be removed by washing with deionized water.

Q: How to improve the precipitation of protein during concentration?

A: Rapid or excessive protein concentration can cause protein precipitation. It is recommended that the final concentration of protein after concentration should not exceed 20mg/ml. For proteins that are sensitive to concentration rate and prone to precipitation, the following improvements are recommended:

1. Reduce centrifugal force to 30% -50% of the recommended maximum centrifugal force
2. Switching to ultrafiltration tubes with lower molecular weight cut-off
3. Multiple short-term centrifugations, repeatedly blowing and suctioning with a gun tip at intervals

Q: What is the reason for the slow filtration speed of ultrafiltration tubes?

A: Unused ultrafiltration tubes contain trace amounts of glycerol in their ultrafiltration membranes. If this situation occurs, please clean with 0.05M NaOH before centrifugation, and then clean the centrifuge again with buffer solution or deionized water. The cleaned ultrafiltration tube should be used immediately. If not in use temporarily, please keep it moist; Used ultrafiltration tubes should be cleaned and kept moist with 20% ethanol for antibacterial preservation. As the number of uses increases, the filtration speed of the ultrafiltration tube will slow down, and a new ultrafiltration tube should be replaced.

Q: After concentration, it was found that there was no target protein in the concentrated solution. What could be the possible reason?

A: Firstly, the minimum starting concentration of protein in the ultrafiltration tube is 30ug/ml. Please ensure that the initial concentration of the sample is greater than this concentration. Secondly, if the problem persists, please do not discard the sample filtrate for analysis of possible causes:

• If the target sample is in the filtrate
  • Have you selected an ultrafiltration tube with a suitable cut-off molecular weight (1/3 of the target protein molecular weight)?
  • Is the centrifugal force used within the specified range?
  • Is this the first time trying this protein? Sometimes the characteristics of the protein itself (conformational differences) affect the concentration effect, and it is recommended to use ultrafiltration tubes with smaller molecular weight cut-off.
• If the target sample is also not present in the filtrate
  • Is the initial concentration of protein sample greater than 30ug/ml
  • Is the target protein precipitated? If so, please refer to the A above regarding protein precipitation for specific solutions.

Q: How to remove endotoxins from ultrafiltration tubes?

A: The provided ultrafiltration tubes have not undergone endotoxin removal treatment. 4ml and 15ml ultrafiltration tubes can be soaked in 0.5M NaOH to remove endotoxins (0.5ml ultrafiltration tubes currently do not support this operation).

Q: There may be non-specific adsorption between the target protein and the ultrafiltration membrane during the concentration process. How can this be improved?

A: The ultrafiltration tube uses polyethersulfone (PES) membrane, which is a material with extremely low protein adsorption for ultrafiltration membranes. For some hydrophobic or non-polar proteins, their non-specific adsorption to the membrane may be enhanced. In this case, we can try to seal the ultrafiltration tube before the experiment or choose a small volume ultrafiltration tube to reduce non-specific adsorption.