Pipetting

There are two main but related methods to pipetting, micropipetting for volumes of 1 ml or less and regular pipetting for volumes greater than 1 ml.

regular pipetting

For volumes 1 ml or greater, especially when the liquid in the container cannot be reached with just the sterile micropipette tip. Usually pipettes come in sizes of 2 ml, 5 ml, 10 ml, and 25 ml.

There are "thumb wheel" and "bulb" manual pipetters and electric pipetters. Currently we have green thumb wheel pipetters in the lab.

I used an electric chargeable Drummond Pipet-Aid (similar to this https://www.pipettes.com/drummond-scientific-pipet-aid-supplied-complete-with-110-v-recharger-ul-csa-approved-plus-four-replacement-filters-and-holster-wall-bracket) at the recent HHMI workshop and was impressed. It fit a range of transfer pipettes sizes and gave a range of control without being too heavy.

micropipetting

Volumes in the 1 µl – 20 µl range should be transferred with a P20 micropipette.

Volumes in the 20 µl – 200 µl range should be transferred with a P200 micropipette.

Volumes in the 200 µl – 1000 µl range should be transferred with a P1000 micropipette.

In general micropipettes work best in the middle of their range (half of their "number", e.g., 100 µl for a p200).

Volumes less than 1 µl can be tricky to work with. Use a P10 micropipette instead of a P20 and/or extended pipette tips if you have them.