One article to master, common failures and treatment methods of pipettes
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Several common failures of liquid extraction
1. There is residual liquid in the pipette suction nozzle:
This situation occurs because the suction nozzle is not suitable, and the original suction nozzle of the pipette should be replaced immediately.
2. The pipette is blocked and the suction volume is too small:
This happens because the liquid has penetrated into the pipette. Clean and lubricate the piston and the pipette connection.
3. Beyond the limited scope:
This happens because the pipette is damaged and should be sent to a repair center for repair.
4. The pipette nozzle ejector is stuck or does not work properly:
This happens because the suction nozzle connecting piece is contaminated. The ejector sleeve should be removed and cleaned with 75% ethanol.
5. The pipette leaks or the pipetting volume is too small:
There are several reasons for this situation:
(1) The piston and O-ring are not sufficiently lubricated.
(2) The pipette is contaminated.
(3) There is a foreign body between the pipette nozzle and the connecting piece.
(4) The pipette nozzle is not suitable.
(5) The pipette nozzle is installed improperly.
(6) The plastic of the pipette nozzle is not evenly wetted.
When pipetting failure occurs:
1. Add appropriate amount of silicone oil.
2. Clean and lubricate the piston and suction nozzle connecting piece.
3. Clean the connecting piece of the suction nozzle and install a new suction nozzle.
4. Use the original suction nozzle.
5. Reinstall it tightly.
6. Install a new suction nozzle.
How to sterilize the pipette?
Although the pipette is small, as one of the routine instruments in the laboratory, it still plays a significant role in the accuracy and precision of our experimental results. Therefore, in order to improve our experimental results, this article will talk about the pipette Disinfection and sterilization treatment. For pipettes, the two concepts of pipette disinfection and sterilization are often confused. In fact, there is a certain difference between the two: disinfection only requires that the live bacteria on the pipette be controlled within a certain range and reach a harmless level; while the sterilization is more stringent, requiring the elimination of all live bacteria . Therefore, the processing requirements for sterilization are higher than those for sterilization.
There are two methods for pipette disinfection:
1. Chemical disinfection
To put it simply, wipe the outer surface of the pipette with alcohol, etc., and then dry it. This should be possible for all pipette brands; if there is a pipette that cannot be disinfected by chemical disinfection, it can only prove that the material of the shell is very poor.
2. Ultraviolet disinfection
It is to irradiate the surface of the pipette with ultraviolet rays to achieve the purpose of disinfection by destroying the DNA structure of the cells. The time of UV disinfection depends on the intensity of radiation and the resistance of bacteria to UV rays. Most brands of pipettes can be sterilized by ultraviolet light, but you still need to confirm with the supplier in advance. Not all pipettes can be sterilized by ultraviolet light.
Tips for using pipettes
1. Use appropriate filter tips
To ensure better accuracy and precision, it is recommended that the pipette volume be within the range of 35%-100% of the pipette tip.
2. Installation of Pipette tips
For most brands of pipettes, especially multi-channel pipettes, it is not easy to install the pipette tip: in order to pursue a good seal, you need to insert the pipette sleeve handle into the pipette tip and turn it left and right or shake it back and forth to tighten it forcefully. . There are also people who use the pipette to repeatedly hit the tip to tighten, but this operation will cause the tip to deform and affect the accuracy, and severely damage the pipette, so such operations should be avoided.
3. The immersion angle and depth of Filter Pipette Tips
The immersion angle of Universal Pipette Tips is controlled within 20 degrees of inclination, and it is better to keep it upright; the recommended immersion depth of the tip is as follows:
Pipette specifications: tip immersion depth 2µL and 10µL 1mm 20uL and 100uL 2-3 mm 200uL and 1000uL 3-6mm 5000µL and 10mL 6-10mm.
4. Suction head rinse
For samples at room temperature, tip rinsing can help improve accuracy; but for samples with high or low temperature, tip rinsing will reduce the accuracy of the operation. Please pay special attention to users.
5. Liquid suction speed
The pipetting operation should maintain a smooth and appropriate suction speed; too fast aspiration speed will easily cause the sample to enter the sleeve handle, causing damage to the piston and seal ring and cross-contamination of the sample.
6. Recommendations for the use of pipettes
(1) Maintain the correct posture when pipetting; do not hold the pipette tightly all the time, use a pipette with a finger hook to help relieve hand fatigue; change hands frequently if possible.
(2) Regularly check the sealing condition of the pipette. Once the seal is aging or leakage occurs, the sealing ring must be replaced in time.
(3) Calibrate the pipette 1-2 times a year (depending on the frequency of use).
(4) For most pipettes, the piston should be coated with lubricating oil before use and after a period of use to maintain the tightness; and for pipettes of conventional volume, it is also ideal without lubricating oil. The tightness.
