Microbiology 345: Proper pipetting techniquesPart A: overview

Find the correct size and type of tip forwhat you will be pipetting. Do not touchthe tip, but firmly put the pipette into thetop of the tip and remove from box.

Draw sample into tip. Pipette sample intoepitube, test tube, or gel.

Use the eject button to discard thetip in the proper tip discard bin.

Pipetted sample.

Part B: using the buttons and dials

A common pipette type. The large button at the top is turned to set thevolume (value shows on the dial display below it). The button is pressedfor drawing and pipetting the sample, and to eject the tip.

Button is not pressed and pipette tipis either empty of completely full.

Button is pressed to first stop. To loador expel a volume into a pipette tip,press the button to the first stop andthen slowly release.

Button is pressed to second(and last) stop. This is usedto eject the empty pipette tip.

Care must be taken when pipetting volumes into tubes that already contain liquid. Touch the pipette tip to the wall of the tube just above the meniscus of theliquid already in the tube. Keep the pipette as straight as possible. Make sure you go to the first stop to expel all the fluid, but don’t go to the second stop!

If you are pipetting into a tube thathas no liquid in it, place your tip atthe button of the tube.

Part C: getting your sample into a tube