Teach you how to use pipettes correctly!

Did you know that if you simply follow these tips, you may be able to improve your pipetting accuracy and repeatability by up to 5%.

Optimal measuring range

The normal operating volume range for most pipettes is (10-100)% of the indicated volume. Although this range is operational, the performance parameters will change as the volume is set. The accuracy parameter for a 100uL pipette is ±0.8% at 50-100% of the indicated volume. However, if you pipette 10 μL (or 10% of the indicated range), the inaccuracy will increase by a factor of 3, or (2.5-3)%. So the optimal range for best performance is 35-100% of the indicated range. Try to avoid setting the volume of one pipette to less than 10% of the maximum volume, and instead use a small volume pipette for small volume pipetting.

Tip immersion depth

The correct tip immersion depth can improve accuracy by up to 5%, which is especially important for micropipettes. For micropipettes, tips should be immersed in (1-2) mm, while for high-volume pipettes, the immersion depth should be (6-10) mm. If the tip is immersed too deeply, the air inside the tip will be compressed, causing too much liquid to be sucked in. Liquid remaining on the surface of the tip may also affect the results. If the tip is not immersed enough, air may be inhaled, which can cause bubble formation and inaccurate pipetting volume. Both can result in inaccurate pipetting volumes

Correct aspiration angle

Aspirate the tip into the sample at a 90-degree angle as much as possible, preferably not more than 20° off the vertical position, and for micro-volume pipettes, pipetting the solution at a vertical angle can improve accuracy by 2.5%. Aspirating more than 20° off the vertical will result in inaccurate dosing – too much liquid will be aspirated, resulting in inaccurate pipetting. Immersing at a 60-degree angle will cause you to absorb more than 0.7% of the liquid you set

Be consistent

Maintaining a consistent pipetting rhythm and speed will help you achieve ideal, more reproducible results. Maintaining consistency in rhythm and speed can improve accuracy by 5%.

Consistent sample dispensing, consistent sample discharge

Be careful to distinguish between rinsing tips and those that are not suitable for rinsing

Rinsing the tip 2-3 times can form a homogeneous film within the tip, which can improve accuracy by 0.2%. Rinsing neutralizes capillary effects in micropipetting, and for large volumes, this brings the internal tip temperature in line with the sample temperature. Rinsing when pipetting hot and cold solutions can adversely affect the results, such as pipetting from an ice bath or when the solution temperature exceeds 37 degrees Celsius, and the rinsing can result in an error rate of up to 5%.

Avoid temperature changes

Constant room temperature: The ideal temperature for pipetting and calibration is 21.5°C ±1°C. Avoid working in areas with wind or direct sunlight and large temperature variations, which may reduce the accuracy of pipetting.

Ensure sufficient equilibration time: Unless otherwise required, ensure sufficient time for your liquid samples and pipettes to reach equilibrium temperature.

Hand Temperature EffectWhen pipettes are used for long periods of time, heat from the hands may heat the pipette, causing the air inside the pipette to expand due to heat, resulting in inaccurate results.