Micropipetting Tips and Tricks

What is a Displacement Pipette?

As a common laboratory tool, an air displacement pipette measures the volume of liquid and is used in standard pipetting applications. Due to high accuracy, the device is suitable for measuring small volumes of aqueous and non-viscous liquids, as compared to organic solvents, which can cause considerable damage. For biological samples such as DNA, RNA, and proteins, an air displacement with filter tips is highly recommended.

An air displacement pipette has six main components, which include:

• Plunger button
• Tip ejector button
• Volume adjustment dial
• Digital volume indicator
• Shaft
• Attachment point for the disposable tip

The piston, on the other hand, is a permanent part of the displacement pipette and can be found in the air-tight sleeve, which releases air when the plunger button is depressed. Upon releasing the plunger button, a partial vacuum is created in the space vacated by the piston. Then, the vacuum pulls the desired volume into the tip and makes it available for dispensing.

BT Lab Systems offers various models of single-channel displacement pipettes, including the P20, P200 and P1000 pipette, which are color-coded for easy identification and calibrated per the standard of EN ISO 8655 for ensured accuracy, precision, and calibration. There are other features as well, including an ergonomic, lightweight design and a Click-Stop digital system for volume setting. 

Features of the P20 pipette

The BT Lab Systems P20 Pipette has a test volume range of 2 to 20 µl and dispenses liquids in increments of 0.1 µl. The pipette has an imprecision percentage of 0.8 to 0.6, and an inaccuracy percentage of 2.0 to 1.8.

Features of the P200 pipette

The BT Lab Systems P200 Pipette is suitable for volumes ranging from 20 to 200 µl and increments of 1 µl. It has an inaccuracy percentage of 0.6 to 0.5, and an imprecision percentage of 0.6 to 0.15.

Features of the P1000 pipette

The BT Lab Systems P1000 Pipette dispenses volumes from 100 µl to 1000 µl and increments of 5 µl. It has an imprecision percentage of 0.7 to 0.2, and an inaccuracy percentage of 2.0 to 0.6.

Micropipetting Tips and Tricks

No matter if you’re using the P20, P200, or P1000 pipette, the following tips and tricks will help you improve your technique:

• Wet the pipette tip before aspirating your first sample so you won’t have a lower volume in the first few samples.
• Immerse the tip below the meniscus during aspiration to prevent air aspiration.
• Pause after each aspiration and leave the tip in the liquid for one second to ensure that you will have the right aspirate volume.
• Use the same plunger speed and pressure when aspirating and dispensing every sample for repeatable results.
• Hold the pipette vertically and avoid touching the sides of the container to prevent wicking and volume loss.
• Examine the pipette tip before and after dispensing your sample.
• Choose -- and use -- the right pipette with the correct tip. You should always match the pipette with the volume range closest to the volume you want to aspirate and dispense. Quality tips with an airtight seal help with reliable liquid delivery. This will improve your accuracy.
• Don’t pipette before liquids and instruments reach an ambient temperature to improve precision.
• Don’t over handle the pipette in order to prevent body heat transfer that can cause variations in sample volumes.

Rely on BT Lab Systems for All Your Displacement Pipette Needs

BT Lab Systems has a broad selection of displacement pipettes, including the P20, P200 and P1000 pipettes. To learn more about single channel pipettes, visit our product page today.