How to use a pipette: Touch off (video)

How to use a pipette: Touch off

Hi there! Anybody, who has ever used an air displacement pipette has encountered this.

After dispensing you'll often see a drop at the end of your tip. What you might not have known, is, that this drop belongs in the dispense and not on the tip. There are three main ways to do this.

A tip touch or sometimes called touch-off, is a common technique used to remove this drop. To do so, the side of the vessel can simply be touched with the tip to remove the draw. Often the tip is kept on the side of the vessel during dispensing and then simply slid back up along the wall. The surface of the dispensed liquid can be touched immediately after dispensing. This can remove the drop.

There's also another way. If the tip opening is completely submerged after dispensing, there is usually no need for a touch-up. Since the drop will remain in the dispensed liquid, once the tip is removed.

Thank you for watching. If you want to know more about pipetting, please watch the next video.


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