Tech Tips for Pipetting
Using a pipette the correct way can lead to better data and more reliable results. Here are a few of the ways you can control variation between wells.
Pre-wet your pipette
For all volumes over 10μL, aspirate and dispense at least 3 times to increase humidity within the tip and reduce the amount of variation by evaporation.
Visually look at amounts of liquid in your pipette
You may be able to tell visually if there is any variation between volumes of liquid in each tip of your multichannel pipette.
Loose tips can cause variation between the volumes of each well and lead to skewed data.
Touch down once
Avoid sliding pipette tips down the side of a well. This can lead to residue clinging to the sides of the wells which leads to background in the well. Instead, just touch your tips down one time in the bottom corner of the well and dispense liquid. Sliding tips in the bottom of the wells can also smear spots leading to unclear results.
Minimize the number of times you have to pipette
Pipette the fewest number of times possible. Choose a pipette volume that will minimize the number of times pipetting into a well. The fewer times you have to pipette, the less chance there is for error.
Minimize bubbles as much as possible
Try not to blow any air into your wells when dispensing the liquid. This is especially critical when adding substrate before imaging.
Pipette large volumes over small
Large volumes are easier to pipette accurately. Pipetting 50μL is more likely to be accurate than pipetting 5μL.
10% rule for accuracy of volumes
Pipettes are less accurate at minimum and maximum settings. Avoid using pipettes for volumes less than 10% of the maximum volume.
Stick to one way of pipetting and do not switch methods during an assay. There are 2 popular ways to pipette:
- Standard or forward pipetting
- Depress plunger to first stop and aspirate. Then dispense to first stop, discard excess.
- Reverse pipetting
- Depress plunger to second stop and aspirate. Then dispense to first stop/ discard excess (this is only if you have enough sample that discarding some liquid is not troublesome).
As researchers and problem solvers ourselves, we understand the value of sound data. We are proud to be a part of research that can better the world. We value the relationships, partnerships, and friendships that we have built with the people who trust and use our technology. We are committed to building these relationships. You can count on us to answer the phone and take time to thoroughly address questions or concerns about any of our products. In an industry that is reputed for grandiose claims, we trust that our quality standards and our customer service set us apart from the competition. If you’re happy with our products or if you think we can do something better, we hope you will let us know.