Use this technique when pipetting viscous liquids or volatile solvents. Reverse pipetting also helps when pipetting ultra-micro samples of 0.5 µL or less. Push the piston down to the purge position (the second stop), then draw the liquid up.
Similarly one may ask, how is a pipette used?
Pasteur pipettes are plastic or glass pipettes used to transfer small amounts of liquids, but are not graduated or calibrated for any particular volume. The bulb is separate from the pipette body. Pasteur pipettes are also called teat pipettes, droppers, eye droppers and chemical droppers.
Are pipettes accurate?
A pipette is accurate to the degree that the volume delivered is equal to the specified volume. Precision, on the other hand, is concerned with the closeness of several measurements to each other, rather than to a standard value, that is the reproducibility of the pipetting samples.
How much does a pipette measure?
The "volumetric" or "transfer" pipette measure a particular volume to high accuracy. (The three pipettes at the top of Figure 1 are volumetric pipettes designed to deliver 25, 20 and 10 mL, respectively.) Volumetric pipettes are designed such after a fluid is dispensed, a small drop of liquid will remain in the tip.