Are you using the right type of micropipette? [How-to]
Micropipettes are essential laboratory instruments used to accurately and precisely transfer volumes of liquid in the microliter range. They are available in mechanical and electronic, as well as in single- and multichannel variants.
What should you consider when choosing a micropipette?
This article guides you through the following most important considerations regarding reliability, efficiency and ergonomics:
- Physical properties of your liquid
- Micropipette size
- Easy calibration
- Volume adjustment locking
- Quality of pipettes and tips
- Color coded pipettes and pipette tips
- Vessels you are using
- Repetitive tasks
- Tip loading and ejection force
- Grip design
- Volume adjustment
Factors increasing reliability
Scientists rely on pipettes that deliver accurate and reproducible pipetting results to guarantee the success of an experiment. Consider the physical properties of your liquid (aqueous, viscous, volatile) as well as the pipette's accuracy and precision to improve your pipetting results.
Physical properties of your liquid:
Most liquids are of the aqueous type, making air displacement pipettes the first choice. Although a majority of liquids will work perfectly well using this pipette type, you may wish to consider positive displacement pipettes if you are working with very viscous or volatile liquids.
Regardless of the liquid type, the correct pipetting technique is essential to achieve excellent results with air displacement pipettes.
The most critical aspects affecting pipetting results are accuracy and precision which can be defined as follows:
Accuracy is the ability of a measuring instrument to give responses to a true value. A pipette is accurate to the degree that the volume delivered is equal to the specified volume.
Precision expresses the degree of reproducibility, or agreement between repeated measurements. If you perform multiple dispenses of a certain volume with a pipette, and it dispenses actual volumes very close to each other, the pipette is precise and your results are reproducible.
For maximum pipetting accuracy and precision, we advise you to look at the following criteria:
Micropipettes are available in different volumes ranging from 0.2 µl to 5,000 µl. As a rule of thumb, always choose the smallest pipette capable of handling the required volume. This is important because accuracy decreases when the set volume is close to the pipette’s minimum capacity. For example, if you dispense 50 µl using a 5,000 µl pipette, you will get rather poor results. Using a 300 µl pipette will give you better results, whereas using a 50 µl pipette would be ideal.
Your micropipettes should be easy to calibrate. Some electronic pipettes have useful features, such as setting a calibration reminder or saving the calibration history.
Are you wondering if your pipette is still working as intended? Follow these guidelines to perform a routine check.
Volume adjustment locking:
Volumes set on traditional manual pipettes can change while pipetting, due to unintentional plunger turns. However, some pipette manufacturers have developed volume adjustment designs that prevent inadvertent volume changes while pipetting.
High quality pipettes and tips:
Do your pipette tips ever loosen, leak or fall off? This is a common issue in laboratories, caused by the use of universal pipette tips. Such tips require ‘hammering on’, which stretches the pipette tip rim. This can cause leaking or misaligned tips, or even cause the pipette tips to fall off the pipette completely! Choosing micropipettes which were designed together with the tips ensures secure connections and tips that do not leak or fall off.
Color coded pipettes and pipette tips:
Color coding helps you to choose the right tips for your pipette.
Factors increasing efficiency
In a high throughput setting, it is important to be as efficient as possible while keeping your pipetting processes reliable and consistent. There are many ways to improve your pipetting efficiency, including the use of multichannel and/or electronic pipettes. Whether or not a multichannel or electronic pipette could benefit your application depends on the following criteria:
What vessels are you using?
Transferring samples between labware of different formats can quickly become very tedious and error-prone using single channel pipettes. Multichannel pipettes allow you to transfer multiple samples at once. This helps you to be much more efficient and also to prevent pipetting errors and repetitive strain injuries (RSI).
Some pipettes are even able to change the tip spacing during pipetting, enabling parallel transfer of multiple samples between different labware sizes and formats. Learn how many hours of pipetting you could save by investing in a VOYAGER adjustable tip spacing pipette.
If you dispense multiple aliquots of the same volume, an electronic pipette could be a great help, allowing repeat dispensing without refilling the tips.
Electronic pipettes usually offer multiple different modes – such as reverse pipetting, variable dispensing, programmed serial dilutions and many more – making your pipetting tasks more efficient.
Factors increasing ergonomics
Pipetting is one of the most common tasks carried out in laboratories, and lab professionals often spend several hours pipetting each day. This can cause discomfort and, in more serious cases, even lead to hand or arm injuries. To avoid these potential risks, consider the following features when choosing a pipette:
Use micropipettes that are lightweight and well-balanced, with the mass in the center for better stability.
Tip loading and ejection force:
Tip loading and ejection often requires more force than pipetting, and presents a potential risk for injuries, especially in high throughput settings. Pipette tips should snap into place with minimal force, provide a secure connection, and eject just as easily.
The pipette should fit comfortably into the hand, for both left- and right-handed users.
Adjusting the volume should be as comfortable and fast as possible, to avoid unnecessary strain on the hands.
Having the pipette in your hand for the shortest amount of time possible should be the goal of any ergonomics-focused task. Learn how the ASSIST PLUS pipetting robot can automate your pipetting tasks.
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