How Accurate are Your Pipettes?

Your pipettes are probably most used tools in your lab and (I’ve said it before, but it’s worth repeating) without accurate pipetting you are asking for problems with your experiments.

Pipette manufacturers quote accuracy of pipettes but the truth is that pipetting accuracy is a very personal thing. It depends not only on the condition of your pipettes but also on your own pipetting technique.

It’s a very useful exercise to periodically measure your pipetting accuracy because this error is incorporated into every pipetting action you perform in the lab.

For most experiments the error might be too small to be significant but in some cases it might be very significant – e.g. if you are using a pipette to measure out a dilution for a very sensitive technique like HPLC.

Put this article into practice

Choose a free resource to help you move forward

EBOOK

Guide to Lab Safety

This ebook introduces you to some of the most common safety principles that you will encounter every time you step into a laboratory. On top of that, it will help point you towards additional resources to answer your questions when deeper questions arise.

GET YOUR COPY

CHEAT SHEET

Guide to Pipette Cleaning

Keeping your pipette clean and sparkling is critical. After all a contaminated pipette could ruin your precious samples in the lab! Download our cheat sheet to get a simple guide to cleaning your pipette. Stick it up in the lab to help remind yourself how to look after this vital lab tool.

GET YOUR COPY

The point is this: to know whether you pipette is accurate enough for the job you want it to do, you need to know the systematic error in your own pipetting.

It’s easy to measure your pipetting accuracy – just pipette the same volume of water ten times onto a tared balance, note the weight each time. Then measure the relative standard deviation in the dispensed masses by calculating the standard deviation and expressing it as a percentage of the average. This is your pipetting error.

Repeat this for several different volumes using each of your pipettes and you’ll get a pretty good idea of your overall pipetting accuracy that you can keep in mind when deciding whether your pipetting is accurate enough for the experiment you are doing.

Dr Nick Oswald

Nick has a PhD from the University Dundee and is the Founder and Director of Bitesize Bio, Science Squared Ltd and The Life Science Marketing Society.

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