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Speeding up pipetting

Today in the lab I was using a multichannel micropipette to speed up a biochemical assay, by transferring solutions to eight wells on a plate simultaneously. Then I took the photo shown below to demonstrate what is probably the worst way to hold a multichannel micropipette for your experiments. Below are some tips on how to eliminate common pipetting errors.

How NOT to hold a multichannel micropipette.
How NOT to hold a multichannel micropipette.

ANGLE: It is important to hold the pipettor upright, because pipetting at an angle past 20º impacts the pressure inside the pipette tip, getting less and less accurate as the angle gets steeper.

DEPTH: Immersing the tip too deep in a liquid can result in droplets on the side of the tip or pressure changes that alter volume. On the other hand, using too shallow a depth while aspirating can lead to air in the tip.

SEAL: A pipette tip that is not properly set on its pipette leads to a poor seal that can dramatically impact volumes.

SPEED: Aspirating too quickly can cause inaccuracies with viscous liquids, lead to air bubbles, or liquid contact with the pipette filter, increasing the chance of contamination. Dispensing a liquid too quickly can lead to splatter or disrupt cells on the bottom of a plate.

CONTACT: Touching tips to the bottom of a well or tube during pipetting can result in incorrect liquid volumes due to blockage of the tip opening. When working with cell lines, accidental contact with a tip can impair cell health. Contact with tips can puncture the filter membranes or damage optical surfaces on plates, impacting imaging and reader performance.

TEMPERATURE: Most pipettors rely on air pressure to move liquids, and air pressure is impacted by changes in temperature. Thus, heat transfer from your hand to your pipette during extended use affects the air between the piston and liquid, making liquid transfers less accurate the longer the pipette is used.