Daily Pipettor Maintenance
Clean pipettors daily by giving them a quick wipe-down with 70 percent ethanol. Give your pipettor a deeper clean about every three months or before performing procedures sensitive to contamination. Refer to the manual to learn how to dismantle, clean, and reassemble your pipettor.
If you need to sterilize or decontaminate your pipettor, look up the proper way to do this depending on the circ*mstances. Some pipettors can be autoclaved.
Pipetting Technique During Experiments
These tips can help you reduce pipetting errors during experiments:
- Push down to attach the tip securely, but don't push so hard that you bend or warp the tip.
- Pre-wet the pipette tip by taking up some liquid and releasing it.
- Don't rush. Always push down and let up the plunger slowly. If you aspirate too fast, you may draw in an air bubble, or you may aspirate liquid into the pipettor body. Dispensing too fast can create aerosols or splashes. It can also damage the cells you're handling.
- According to an article in Bioinformation, an improper immersion depth or angle can decrease pipetting accuracy. Keep the pipettor in a vertical position while aspirating liquid, but hold it at a 30- to 45-degree angle while dispensing liquid. Never tilt the pipettor so far that liquid could run into its body. Look up the correct immersion depth for the volume you're pipetting, and use this depth consistently.
- After lifting the plunger, pause briefly with the tip under the surface to allow liquid to finish filling the tip. Since evaporation will also occur from the liquid surface inside the tip, try to keep this pause as consistent as possible from sample to sample.
It's also important to prevent fluctuating environmental conditions in the lab. Variations in laboratory environmental conditions like temperature, relative humidity, and barometric pressure can cause changes in pipetting accuracy from day to day.
Forward and Reverse Pipetting
Forward pipetting is the most common pipetting technique, and it should be used for most aqueous solutions. To forward pipette, push the plunger down to the first stop, no further. At the correct immersion depth, slowly draw in liquid. Then dispense the liquid, pushing the plunger down to the second stop to get all of the liquid out of the tip.
Reverse pipetting is an alternative technique that provides a volume cushion, and it can help when you're pipetting viscous, volatile, or foaming liquids or handling very small volumes. To reverse pipette, push the plunger down to the second stop. Then immerse the tip and slowly release the plunger to draw in liquid. To dispense, push the plunger to the first stop only. Discard the excess liquid left in the tip, or return it to its container.
Choose the Right Pipettor and Store It Correctly
In addition to recognizing improper pipettor maintenance and technique, understanding other common mistakes can help you learn how to reduce pipetting errors. These mistakes include choosing the wrong pipettor size and tip for the volume you're handling and storing pipettors incorrectly.
Pipettor Size
Pipettors come in different sizes, typically ranging from 0.1 μl to 1000 μl or more. Use the smallest pipettor that can handle the volume you want to dispense — accuracy and precision decrease near the bottom of each pipettor's volume range. For instance, instead of using a 10-100 μl pipettor to dispense 10 μl of liquid, choose a 0.5-10 μl pipettor.
Dispensing tiny volumes with accuracy and precision is difficult. Consider diluting your sample so you can pipette a larger volume of liquid but arrive at the same concentration in the final mixture.
Pipettor Tip
Choose a tip whose material and shape are suited to the substance you're handling and its viscosity. If you're using corrosive samples that evaporate, use a filtered tip to protect the pipettor. Filtered tips can also be useful for preventing cross-contamination between samples.
Pipettor Storage
When not in use, store pipettors properly on a stand that keeps them upright.
Finding Pipettors, Pipette Tips, and Resources
Corning offers a wide array of pipettors and tips, plus guides and resources to help you improve your liquid handling techniques and choose the right products. Explore the Corning catalog to find the pipettors you need today.
