Suppressing and controlling electrostatic charge in micropipetting

Abstract

Commonly used liquids have a powerful effect on producing electrostatic charges, from laboratory routines to industry processing and everyday activities. In many situations, electrostatic charges are not desirable, mostly in the presence of flammable liquids or for electronic devices that are susceptible to electrostatic discharge (ESD). Recently, liquid water was successfully allocated in the triboelectric series and it was shown that it can acquire great amounts of charge when flowing through different materials or even by a simple micropipetting. Here, we have developed a simple but robust protocol to suppress and control electrostatic charges during the pipetting of water, common alcohols and solutions. Using glass containers instead of plastic ones, charge is highly suppressed and its sign and magnitude can be controlled with external electrical fields. Finally, drops arising from a micropipette ended in a grounded metallic needle have roughly zero net charge, regardless the presence of external electrical fields. This protocol faces a very challenging problem of electricity formation while handling common liquids and it could be helpful to avoid electrostatic charge in many systems.