Reagent

In biochemistry, especially in connection with enzyme-catalyzed reactions, the reactants are commonly called substrates.

Purity standards for reagents are set by organizations such as ASTM International or the American Chemical Society.

For instance, reagent-quality water must have very low levels of impurities such as sodium and chloride ions, silica, and bacteria, as well as a very high electrical resistivity.

Laboratory products which are less pure, but still useful and economical for undemanding work, may be designated as technical, practical, or crude grade to distinguish them from reagent versions.

In the field of biology, the biotechnology revolution in the 1980s grew from the development of reagents that could be used to identify and manipulate the chemical matter in and on cells.