"Pipetting at an angle can cause an error. Touching the pipette tip to the container sides during aspiration results in loss of sample. In addition, removing the pipette at an angle can cause volume variation due to surface tension effects, especially when pipetting small volumes. Pulling the pipette straight out of the container can minimize error."

Pipettes, also called pipets or chemical droppers, are small tubes of glass or plastic used to transfer a measurable amount of liquid from one container to another. They come in two forms: volumetric pipettes, used to transfer a single specific volume of liquid, and measuring pipettes, used to transfer varying, measured volumes. Share an example of a common error.

"If pipette operators do not pre-wet the pipette tip prior to initial delivery, sample volume can be lost due to evaporation within the tip. Aspirating and expelling sample liquid at least three times before delivery can mitigate this risk, and is especially important when handling volatile solutions such as organic solvents."