First, we need to determine if the pipette is leaking.
1. Detection method:
1) Visual inspection: first suck up the liquid with the pipette to be tested, and then place it vertically for 15 seconds to observe whether any droplets slowly flow out. If the droplets come out slowly, it means the pipette is leaking.
2) Pressure pump detection: Use a special pressure pump to detect the pressure to determine whether the pipette is leaking.
2. If the pipette leaks, then we need to analyze the possible causes of the leak:
First, check if the prompts match? It is recommended to use the original matching tips. If it is not the original matching tip, it is best to consult the manufacturer or agent to see if the tip you are using matches the pipette you are using.
Second, was it tightened when assembling the tip? Pipettes may leak due to not tightening the tips during installation.
Finally, if no problem is found in the above two cases, it is likely that the airtightness inside the pipette is not good. In this case, you need to contact the maintenance engineer of the pipette company.
After we have ruled out the first case above, we want to investigate the second case:
We need to detect whether the temperature of the pipette and whether the temperature difference between the pipette and the pipette tip affects the accuracy of the pipette.
Normally, when the pipetting temperature does not coincide with the temperature of the tip and pipette, the following two differences occur:
1. When the liquid temperature is higher than the tip, the pipetting volume will be too large;
2. When the liquid temperature is lower than the tip, the pipetting volume will be too small
If the second case is ruled out, then we have to investigate the following third case:
Observe whether the density of a liquid sample is significantly different from that of water?
Generally, pipettes are factory calibrated with water as the standard for testing. Therefore, if the specific gravity of the liquid being manipulated differs greatly from that of water, the precision and accuracy given may not be met. An error occurred.
After all the above problems are eliminated, you should also pay attention not to inhale too fast. Aspirate too fast can cause backwash and air bubbles, which can lead to inaccurate pipetting volumes and ultimately affect the accuracy of the pipette.