Nitrogen is a chemical element and is a colorless, odorless, tasteless, and mostly inert diatomic gas at standard conditions, constituting 78.08% by volume of Earth’s atmosphere. Liquid nitrogen is a cryogenic liquid. Like dry ice, the main use of liquid nitrogen is as a refrigerant. Among other things, it is used in the cryopreservation of blood and other biological samples and materials.

Nitrogen gas has a variety of applications, including serving as an inert replacement for air where oxidation is undesirable, as a modified atmosphere, pure or mixed with carbon dioxide, to preserve the freshness of packaged or bulk foods and manufacturing of stainless steel.

Nitrogen is commonly used during sample preparation procedures for chemical analysis. It is used to concentrate and reduce the volume of liquid samples. Directing a pressurized stream of nitrogen gas perpendicular to the surface of the liquid allows the solvent to evaporate while leaving the solute(s) and un-evaporated solvent behind.