January 30, 2022

Pipette Paradise!

The most revolutionary device of all mankind is the pipette; well known for its use in biology or chemistry labs, pipettes are respected in all corners of the science world. All pipettes have a couple things in common: they move liquids aseptically and accurately. You may wonder why there are so many pipettes if they all do the same thing. Well, it's because not all liquids and protocols are alike. You may need 1 microliter or 20 milliliters, or maybe you need to move bacteria instead of highly reactive reagents. This variety makes it necessary to create multiple tools. The 3 most common varieties of pipette are the transfer pipette, the micropipette, and the serological pipette.

Transfer Pipette

Disposable Transfer Pipette - Fisher Scientific

The transfer pipette is the simplest of the 3 as it doesn't pick up as accurately as most other pipettes. Its usefulness, however, comes from its ability to easily pick up liquids. This means a mini-lecture isn't required to use the pipette. This is also why most students are first exposed to the transfer pipettes. All in all, it's an alright pipette.


Single Channel Micropipettes - Eppendorf

The micropipette is the most diverse category of pipettes and rightfully so! They come in 3 variants to accomplish different goals. Micropipettes, which are more commonly seen in biology labs, can accurately pick up very small quantities of liquids aseptically with amounts as low as 1 microliter.

As mentioned, the 3 variants of micropipettes are the single channel, multichannel, and repeating. The single channel is the most basic and can pick up and put down a set volume each time. Its usefulness comes in its simplicity. The multichannel is a micropipette that can pick up from multiple sources at once. While bulky, it is very useful for conducting assays since it would take ages to pick up each reagent separately using a single channel pipette. The repeating is similar to a standard micropipette, however, it can put down select volumes of liquids, reducing the need to pick up multiple times. It's useful when having to fill multiple tubes with equal amounts of liquid (when doing dilutions for example).

Serological Pipette

Manual Serological Pipette - SP Bel-Art

The serological pipette does the opposite of the micropipette: it picks up large amounts of liquids (1 milliliter to about 50 milliliters). It's arguably the most annoying to use due to its length and difficulty to maintain aseptic technique. Most students, however, don't care about being aseptic but only enjoy the idea of utilizing a large glass needle (or burette for chemistry nerds).

The serological pipette uses a pump to pull up air and create a vacuum. These pumps come in 2 variants as well: manual and automatic. A manual pump utilizes a scroll wheel to pull in liquids and dispense accurate amounts. This type of pump is more commonly given to students since it's affordable and hard to break. An automatic pump, also known as a pipette aid or pipette controller, is a motorized version of the serological pipette that is controlled with 2 buttons. Its superiority comes from the fact that it minimizes human error. While a manual pump requires precise scrolling, an automatic is more stable and is much simpler to use (with proper training of course).

Closing Remarks

While there may be many more types of pipettes, the 3 most common types are shown here. These are used in every lab and are a staple in everyone's laboratory experience. Of all of the types and varieties, I'd argue that the repeating micropipette is the coolest. It's sleek, it's versatile, and it has the added benefit of repeating when compared to a single channel micropipette. However, it all comes down to what the lab ahead is!