Good Pipetting Practice
Pipetting Techniques to Boost Your Performance
Improve your data quality with Good Pipetting Practice™ (GPP™) – METTLER TOLEDO’s comprehensive, systematic approach to maximizing pipetting accuracy and repeatability.
GPP covers many topics relevant to life science researchers or anyone using pipettes regularly:
- Understand the array of pipettes and liquid handling instruments and options available
- Know how to optimize your pipetting workflow
- Gain the range of pipetting skills necessary to produce reliable data
- Appreciate how pipetting ergonomics can influence data production and your own well being
- Recognize the risk associated with out-of-calibration pipettes and the role of routine pipette checks vs. professional pipette service.
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Five Pipetting Techniques to Boost your Performance
The following tips and tricks are a short excerpt of one of the many topics covered in our GPP seminars and elearnings.
Here are some very common pipetting technique errors and how to avoid them.
1. Wrong tip immersion depth The correct tip immersion depth can improve accuracy by up to 5%. The tip should be immersed between 1-2 mm for micro-volume pipettes and up to 3-6 mm for normal-range pipettes, depending on the tip size. If the tip is immersed too far, the volume of gas in the tip is compressed, causing too much liquid to be aspirated.
2. Wrong pipetting angle The immersion angle of your pipette tip in the sample should be as near to vertical as possible and should not deviate more than 20 degrees from vertical. A more horizontal angle causes too much liquid to be drawn into the tip, resulting in inaccurate aspiration. For example, at an angle of 30 degrees to vertical, up to 0.7% too much liquid can be aspirated.
3. Inconsistent dispensing Greater accuracy and sample-to-sample reproducibility can be achieved by ensuring that the last remaining droplet dispenses fully and does not adhere to the tip end. For most applications, dispensing with the end of the tip resting against the vessel wall is recommended as it reduces or eliminates the amount of sample remaining in the tip. This technique can increase accuracy by 1% or more.
4. Failure to pre-rinse Dispensing liquid from a pipette leaves a coating of the liquid on the tip, making the expelled volume slightly less than it should be. Pre-rinsing a new tip at least twice with the liquid about to be used will condition the inside of the tip.
5. Inconsistent pipetting rhythm Use a consistent pipetting rhythm from sample to sample. Avoid hurrying or rapid operation and get into a rhythm for each step in the pipetting cycle.
These five simple techniques alone can have a big impact on your results, but there are a few more to consider.
As part of our Good Pipetting Practice™ program, METTLER TOLEDO has developed a quick Risk Check to help you assess your personal pipetting risks and learn how to reduce them. You'll get a personalized Risk Analysis Report that you can view and print online.
GPP is all about helping you learn to improve your pipetting accuracy and recognize when your pipettes are not working properly.
Access pipetting brochures and other pipetting knowledge material around Good Pipetting Practice.