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Pipetting 101


One of the most important laboratory tools, a pipette is used in a wide variety of different industries to make transferring liquid safer and easier, but it’s not always clear how to use them. In this blog, we’ll show you the exact way your pipette should be used to ensure accurate and safe pipetting with every use. 

Need help choosing a pipette for your application? See our full guide to choosing the right pipette for your lab needs.  

What is a Pipettes

Pipettes, which are often used in biology and chemistry laboratories, are essential to completing many experiments. Pipettes can work differently, depending on the type of pipettor used. Most pipettors, though, operate by creating a partial vacuum of air above the liquid holding chamber, which is then released selectively to help draw and dispense the liquid. Extremely accurate liquid measurement is vital in the laboratory, and pipettes provide that. 

What are the Different Types of Pipettes? 

Pipettes can come in a wide variety of designs and types, including disposable transfer pipettes, electronic pipettes and multi-channel pipettes. So how do you know which one is the right choice? The functions, volume, and type of liquid you are dealing with will help you determine which type of pipette to purchase. Below are several types of pipettes you may find.  


Volumetric Pipettes: Also known as "Transfer Pipettes," these are generally used for experiments involving chemical properties and analyzing reactions. Volumetric Pipettes can be found in most universities, classrooms, and professional laboratories. With the ability to measure up to four significant figures, this easy-to-use type of pipette is economical, accurate and available in a wide range of sizes to fit most needs. 


Serological Pipettes: Serological pipettes are frequently used in the laboratory for transferring volumes of liquid from less than 1 ml to up to 50 ml. These type of pipettes can include sterile, glass or reusable pipettes that may come in disposable packaging.


Graduated Pipettes: These pipettes feature molded-in graduation marks that show incremental volume measurement marks along their length. These marks do not fade or wash off. 

Vacuum Assistant Pipettes (Graduated & Volumetric): Vacuum-assisted pipettes are very common and can come in graduated or volumetric designs. Graduated vacuum-assisted pipettes display multiple graduation marks on the outside, while volumetric pipettes only measure a single volume, exhibiting just one graduation mark. These pipettes – which are made from polystyrene, glass or borosilicate – require a suction device but don’t contain any pistons. 

How to Properly Use a Pipettor

https://www.youtube.com/watch?v=uEy_NGDfo_8

To effectively use your pipettor and maintain accuracy, it is important to always follow the steps below in a controlled environment or laboratory setting. 

This video above showcases pipetting for micro pipettors, however, the general steps and methodology remain the same for other pipettes.

Before You Start:

Before you begin, make sure that you have all the necessary tools and equipment to perform your pipetting. This includes:

  • A pipette
  • Pipette tips
  • Container holding the solution you wish to pipette
  • Empty container for the solution(s) to be transferred into 
  • Clean working space
  • Proper waste bin.
  • Gloves for potentially hazardous materials.

Using a Pipettor:

Almost all pipettes will have two “stops” on the plunger. It’s a good idea to play with the plunger beforehand to get a feel for these two different stops. The first stop is the amount or volume that you wish to transfer. The second stop acts as an extra “push” that it sometimes needed to remove all the excess liquid from the tip.  

  • Set the correct volume on the pipette, then gently depress the plunger or push the button until you feel resistance.  
  • Next you will want to make sure you have the correct tip size. Once you have selected the right size, place the end of your pipette on top of the pipette tip and press firmly until the tip is securely attached.
  • Carefully immerse the pipette tip to the correct depth (this can vary by the pipette and tip), and slowly let the plunger go back to its resting position. Allow about one second for the liquid to flow into the tip.
  • Put the pipette tip, now being held at 10–45 degrees, against the wall of the receiving chamber, and gently depress the plunger to the first stop. It's important to avoid touching the sides of the container.
  • Allow another second, then carefully depress the plunger to the second stop to dispense any excess liquid in your pipette tip.
  • Finally, to dispose of the pipette tip properly, press the tip ejector button (usually next to the plunger) while over a waste bin to release or force the tip off of the pipette.

Don't Forget

It's very important to remember to avoid common mistakes such as:

  • Don’t use a pipette without a tip attached
  • Don’t jam the pipette tip into the pipette
  • Don’t use a pipette past its volume limits

Some of these may seem like common sense, however, these are especially important to remember because not using a pipette without a proper tip secured can damage the interior of the pipette and provide inconclusive samples and results. The most common pipetting errors result from the careless use of pipette tips, inconsistent rhythm or timing, and improper handling.

Shopping for your Pipette

Sonic offers a wide selection of pipettors for your needs, from electronic and transfer pipettes, to disposable pipettors and even linear stands for storing your pipettes. If you are having difficulty finding the proper pipette tips after purchasing your pipettor, check out Globe Scientific's Pipette Tip Selection Guide.

Questions?

Feel free to contact us anytime, or call us at 1-844-977-6642

Globe Scientific Pipette Tip Selection Guide

How to choose pipettes

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