Pipets (or pipettes) are laboratory and medical instruments used in the measurement and transfer of liquid. Pipettes come in different designs based on the intended purpose with varying levels of accuracy and precision. These tools work by creating a partial vacuum above the liquid-holding chamber and releasing this vacuum to draw up or dispense liquid. Our guide to chemistry transfer pipets is available for reference. When printed, it illustrates to-scale renditions of general purpose, graduated, fine tip, narrow stem and paddle pipets. Please print the PDF file to ensure accuracy.
As is visible in the pipet guide, most resemble large eye droppers with a vacuum component (or piston) that draws liquid into the holding chamber. This portion of the pipet is typically composed of glass or plastic.
There are several varieties of pipets and each is outlined below.
Volumetric Pipets record the most accurate measurements due to their long, narrow design. The volumetric pipet is used to deliver its contents exactly as specified.
Graduated pipets, also called Mohr pipets, include graduated markings to measure various volumes. The graduated pipet measures volumes by subtracting the final volume from the initial one. The 0 milliliter point at the dispensing end, called dead volume, is the baseline for all measurements.
Serological Pipets, or blow-out pipets, differ from the graduated variety because they have no 0 milliliter baseline. Calibration markers extend the entire length of the holding chamber to the tip.
Pastor pipets are only used to transfer liquids because there are no markings for measurement. Most plastic transfer pipets are convenient for a variety of liquid handling tasks when precise measurement is not needed. They are also quite durable and gentle. Most are unbreakable, freezable, and won't scratch cuvettes.
More advanced features and styles include motorized pipets and mechanical pipettors. Follow the links provided for additional information on those products.
Have more questions about pipets? Contact us toll free at 800.922.7558.