Stocking Up on Lab Supplies: Pipettes and Styles of Pipettes
One of the most commonly used lab supplies is the pipette that transfers specific volumes of fluids. According to our technical application specialists, you can choose from the following types of pipettes:
Cole-Parmer® Sterile Pipette, Individually Wrapped, Plastic White TD Ring
Disposable Pipettes:
Transfer Pipettes/Pasteur Pipettes transfer small quantities of liquids. Plastic bulb pipettes are typically not precise enough to be used for exact measurements but their glass counterparts can be extremely precise. The longer and thinner the tip of a glass pipette is the more exact the measurement. Generally, this type of pipette is considered inexpensive enough to be disposable. However, as long as the glass point is not chipped, the Pasteur pipette may be washed and reused indefinitely. The volumes are usually marked on the stem, though the markings are not particularly accurate.
Serological Pipettes have a plain, narrow tube which extends to a tip and graduates uniformly along its length. With a Mohr pipette, calibration marks may be confined to the stem. With a serologic pipette, they may extend to the tip.
Volumetric Pipettes offer very accurate volume measurement of a solution. They have a large bulb with a long narrow portion. This portion has a single graduation mark, as it is calibrated for a single volume such as 10, 25, and 50 mL. These pipettes are commonly used in analytical chemistry to make laboratory solutions from a base stock as well as prepare solutions for titration.
Pipetting Aids are used with disposable pipettes. These aids range from a basic rubber bulb to electronic controllers that help ease the repetitive nature of some pipetting applications.
Single Channel vs. Multichannel Pipettes:
These are determined based on the total number of pistons in the pipette. For manual high-throughput lab applications, most would prefer a multichannel pipette instead of a single channel, which would require filling well by well.
Manual vs. Electronic:
Electronic pipettes were developed to improve ergonomics by reducing the necessary force. The manual movement of the piston is replaced by a small battery-powered electric motor. Whereas manual pipettes need a movement of the thumb (up to 3 cm), electronic pipettes use a main button.
Fixed vs. Adjustable Volume:
Adjustable volume pipettes are the most common type. They can be set to a specified volume within their operational range, generally10 - 100 µl. Exceeding the limits of the pipette may result in damage. The fixed volume pipette cannot be changed. Fixed volume pipettes have less moving parts and typically offer more accurate volume measurement.
Repeat Pipettes:
These specialized pipettes are used for serial or repeat applications. In general, they have specific tips which do not fit normal pipettes. Pipettes are typically listed with two volumes: the first indicating the total volume that can be held followed by the subsequent adjustable dispense volumes.
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