Accurate and precise pipetting is fundamental to laboratory work, ensuring reliable results in various scientific applications. However, deviations in pipetting volumes can lead to frustrations and potential inaccuracies. In this article, we will delve into abnormal pipetting volumes, explore possible causes, and outline systematic steps for diagnosing and resolving such issues. Whether you are an experienced researcher or a laboratory novice, understanding these troubleshooting techniques can greatly enhance your pipetting experience and contribute to the integrity of your experimental results.
Oversized Pipetting Volume:
Oversized pipetting volumes are relatively rare but may occur due to two main reasons:
Operator Error: This occurs when the pipette's suction/dispensing button is continuously pressed instead of being pressed to the stop point (not fully pressed).
Pipette Calibration Issue: The pipette may require calibration using appropriate tools to adjust the volume settings.
Undersized Pipetting Volume:
Undersized pipetting volumes are a common issue and may result from various factors. Here is a systematic approach for diagnosing and resolving the problem:
Check Pipette Tips: Ensure that the pipette tips are properly attached and not deformed. Try using new, visually undamaged tips to see if the issue persists. If the pipetting volume is still insufficient, proceed to the next step.
Inspect the Shaft: Check the surface where the shaft connects with the pipette tip. If there are minor scratches due to prolonged friction or if the surface feels rough, consider replacing the shaft. Also, ensure that the shaft is not obstructed. Remove the shaft, hold it with the wider end facing your eye and the narrow end facing a light source. If you cannot see light passing through, the shaft is obstructed. Clear the blockage using a thin metal plate. Once the shaft is confirmed to be normal, check if the pipetting volume is still insufficient. If the problem persists, move to the next step.
Check the Seal of the Pipette: Set the pipette's volume range to the maximum and attach a tip. For pipettes with a volume range of 200 μL and above:
Draw up water and hold vertically for 15 seconds. Check for the formation of water droplets or dripping from the tip. If no change is observed, the seal is good.
For pipettes with a volume range below 200 μL:
Draw up water using a pipette and immerse the tip in water for 15 seconds. Observe if the liquid level inside the tip decreases. If there is no dripping, the seal is good.
If the pipette seal is intact but the pipetting volume is still insufficient, contact the supplier to adjust the pipetting volume setting using appropriate tools. If the seal is incomplete, proceed to the next step.
Check the Piston System: Remove the piston and inspect for contamination. Before reassembly, clean the piston and apply lubricant. Check if the pipetting volume is now correct. If the problem persists, involve the supplier for further resolution.
For more severe issues such as aging seals or rusted pistons, seek assistance from the supplier.
In conclusion, troubleshooting abnormal pipetting volumes requires a systematic approach. Start with simple checks and progress to more complex steps, involving the supplier when necessary to ensure accurate and reliable pipetting results.
Oversized Pipetting Volume:
Oversized pipetting volumes are relatively rare but may occur due to two main reasons:
Operator Error: This occurs when the pipette's suction/dispensing button is continuously pressed instead of being pressed to the stop point (not fully pressed).
Pipette Calibration Issue: The pipette may require calibration using appropriate tools to adjust the volume settings.
Undersized Pipetting Volume:
Undersized pipetting volumes are a common issue and may result from various factors. Here is a systematic approach for diagnosing and resolving the problem:
Check Pipette Tips: Ensure that the pipette tips are properly attached and not deformed. Try using new, visually undamaged tips to see if the issue persists. If the pipetting volume is still insufficient, proceed to the next step.
Inspect the Shaft: Check the surface where the shaft connects with the pipette tip. If there are minor scratches due to prolonged friction or if the surface feels rough, consider replacing the shaft. Also, ensure that the shaft is not obstructed. Remove the shaft, hold it with the wider end facing your eye and the narrow end facing a light source. If you cannot see light passing through, the shaft is obstructed. Clear the blockage using a thin metal plate. Once the shaft is confirmed to be normal, check if the pipetting volume is still insufficient. If the problem persists, move to the next step.
Check the Seal of the Pipette: Set the pipette's volume range to the maximum and attach a tip. For pipettes with a volume range of 200 μL and above:
Draw up water and hold vertically for 15 seconds. Check for the formation of water droplets or dripping from the tip. If no change is observed, the seal is good.
For pipettes with a volume range below 200 μL:
Draw up water using a pipette and immerse the tip in water for 15 seconds. Observe if the liquid level inside the tip decreases. If there is no dripping, the seal is good.
If the pipette seal is intact but the pipetting volume is still insufficient, contact the supplier to adjust the pipetting volume setting using appropriate tools. If the seal is incomplete, proceed to the next step.
Check the Piston System: Remove the piston and inspect for contamination. Before reassembly, clean the piston and apply lubricant. Check if the pipetting volume is now correct. If the problem persists, involve the supplier for further resolution.
For more severe issues such as aging seals or rusted pistons, seek assistance from the supplier.
In conclusion, troubleshooting abnormal pipetting volumes requires a systematic approach. Start with simple checks and progress to more complex steps, involving the supplier when necessary to ensure accurate and reliable pipetting results.
next: Addressing Liquid Retention in High-precision Pipette Tips
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