Pipette - Definition and Overview

A pipette with a squeeze bulb on the end

A pipette is a glass tube used for the delivery of a measured quantity of liquids. There are two kinds of pipettes, a kind with a bulbous middle section that has a single mark for the quantitative delivery of a single volume of liquid each time, and another that has many graduated marks, much like a graduated cylinder, that can deliver moderately accurate volumes (to within a few percent) of liquids in variable amounts.

A pipette used for the delivery of small fractions of a milliliter of liquid is called a micropipette. Many methods are employed in measuring small amounts of liquids but air deplacement is the most popular.

A modern (Gilson) pipette in use

Rainin (a division of Mettler Toledo) is the world's largest developer & supplier of pipettes.

A Pasteur pipette is a cotton-plugged glass tube drawn out to a fine tip, used for the sterile transfer of small volumes of fluid. The liquid is usually drawn up into the pipette by mouth, although this is now less common due to safety concerns.

Modern pipettes, sometimes called Gilson pipettes, often use a mechanical plunger and can be calibrated to deliver a fixed amount of liquid with each stroke.

See also

• chemistry