What consumables are required by almost all laboratories? In short, there must be centrifuge tubes! Disposable centrifuge tubes are one of the most commonly used laboratory consumables in the fields of biology and chemistry. It can be said that every biochemical laboratory needs to use centrifuge tubes. They are mainly used for the separation, preparation, and storage of various experimental samples and come in various specifications based on the volume of samples they hold. So, how should we choose centrifuge tubes?
Disposable Centrifuge Tubes Consist of a Tube Body and a Tube Cap
The tube cap comes in two types: attached caps and separate caps.
Attached caps are integrated with the tube body for easy one-handed operation and are generally for 2mL and below specifications centrifuge. Separate caps use a screw cap design, and some products have rubber gaskets inside the cap for better sealing. It is recommended to place the cap facing upwards during use to prevent contamination, and they are generally for specifications of 2mL and above disposable centrifuge tubes.
The tube body can have either a pointed or round bottom.
A pointed bottom allows liquids to concentrate more, making it easier to draw off all the liquid when pipetting. A round bottom can better withstand pressure, and round bottom centrifuge tubes have better resistance to high-speed centrifugation compared to pointed bottom tubes.
From the Overall Structure of Disposable Centrifuge Tubes
Standing tube bottoms: can be directly placed upright on the table for convenient use.
Non-standing tube bottoms: require the use of a centrifuge tube rack or must be inverted to stand on the table.
Tubes with graduation marks and writing areas: provide a reference for approximate volume, saving measurement time for experiments that do not require precise quantification.
Differences Among Disposable Centrifuge Tubes of Different Colors
Transparent centrifuge tubes: suitable for regular samples;
Brown centrifuge tubes: brown tubes have some light-blocking properties, offering certain protection for light-sensitive reagents and those that decompose or react easily under light.
Choose Based on Capacity
Common capacities for disposable centrifuge tubes are 1.5mL, 2.0mL, 15mL, 25mL, 50mL, etc. Choose based on the volume of sample required for the experiment. Note that centrifuge tubes should not be overfilled, generally not exceeding 2/3 of the tube's volume. However, in certain situations, such as ultra-high-speed centrifugation, the tube needs to be filled to prevent deformation.
Choose Based on Material Chemical Compatibility
The disposable centrifuge tubes we use now are basically made of plastic. Common materials include polypropylene (PP), polyamide (PA), polycarbonate (PC), and polyethylene terephthalate (PET).
PP material centrifuge tubes can withstand high speeds, be sterilized at high temperatures, and resist most organic solvents. Therefore, most centrifuge tubes on the market are made of PP material.
Choose Based on Relative Centrifugal Force
Disposable centrifuge tubes have a maximum speed they can withstand. When looking at the working rate of a centrifuge tube, it is best to look at RCF (relative centrifugal force) rather than RPM (revolutions per minute), as RCF takes gravity into account while RPM only considers the rotor's rotational speed.
So when choosing disposable centrifuge tubes, calculate the maximum centrifugal force you need to find the appropriate tube. If you do not need very high speeds, you can choose a centrifuge tube with lower centrifugal force, which will also be cheaper to purchase.
