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Mastering the correct use of ultrafiltration centrifuge tubes is the key to ensuring the success of experiments
Date: 2025-12-01Read: 3
Ultrafiltration centrifuge tube is a laboratory consumable that integrates centrifugation and membrane separation technology, widely used in biochemical operations such as protein concentration, desalination, buffer displacement, nucleic acid purification, and small molecule removal. Its core is an ultrafiltration membrane with a specific cut-off molecular weight, which drives the sample through the membrane pores through centrifugal force to achieve efficient separation of target molecules. However, improper operation can easily lead to membrane blockage, sample loss, low recovery rate, and even tube rupture. Mastering the correct usage method is the key to ensuring the success of experiments.
1、 Preparation before use
Accurately select membranes based on molecular weight: target macromolecules should be 2-3 times larger than MWCO, and small molecule impurities should be less than 1/2MWCO to ensure effective interception and permeation;
Wetting the membrane surface (if necessary): For hydrophobic membranes (such as PVDF), add a small amount of buffer solution or ethanol to wet for 5 minutes, and then centrifuge to remove to avoid air resistance affecting the flow rate;
Check the integrity of the tube body: Confirm that the filter membrane is not damaged and the sealing ring of the tube cover is intact to avoid centrifugal leakage.
2、 Sample loading specifications
Control the sample volume: usually not exceeding 75% of the maximum capacity of the centrifuge tube (such as 15mL tube sample addition ≤ 11mL), reserve concentration space;
Pre clarification treatment: Samples containing particles or cell debris need to be centrifuged at low speed (e.g. 3000 × g, 5 minutes) or filtered to prevent membrane pore blockage;
Avoid direct sample loading with high viscosity or concentration: it can be diluted appropriately to increase the initial flux.
3、 Centrifugal parameter setting
Refer to the manufacturer's recommended speed: usually 3000-5000 × g, overspeed is strictly prohibited (check the maximum RCF value marked on the pipe wall);
Set appropriate time: centrifuge in stages (e.g. 10-15 minutes each time), observe the volume of concentrated solution, and avoid dry film;
Low temperature operation: For thermosensitive proteins, use a 4 ℃ freeze centrifuge to prevent denaturation.
4、 Concentration and washing operation skills
Buffer replacement: When concentrated to about 100-200 μ L, add an equal volume of new buffer, mix well, and then centrifuge. Repeat 2-3 times to remove>95% small molecule impurities;
To avoid membrane drying up: at least 50 μ L of liquid should be retained at the concentration endpoint, and the dry membrane will irreversibly reduce the recovery rate;
Gently mix: Use a pipette to slowly blow and strike, without violently shaking and damaging large molecules.
5、 Recycling and cleaning (if reusable)
Most ultrafiltration centrifuge tubes are designed as disposable, but some models can be reused;
Immediately rinse with deionized water after use, then soak in 0.1M NaOH or specialized cleaning solution to remove residue;
High pressure sterilization or drying is strictly prohibited to prevent deformation of the membrane structure.