1. The process of extinguishing, removing, or diminishing a physical property such as heat or light; e.g., the cooling of a hot metal rapidly by plunging it into water or oil.
2. In beta liquid scintillation counting, the shifting of the energy spectrum from a true to a lower energy; it is caused by a variety of interfering materials in the counting solution, including foreign chemicals and colouring agents.
3. The process of stopping a chemical or enzymatic reaction.
Origin: M. E. Quenchen, fr. O.E. Acwencan
fluorescence quenching, a technique used in investigations dealing with binding of antigens (haptens) by purified antibodies, applicable in cases in which the bound antigen (hapten) absorbs (quenches) light emitted during fluorescence of protein (antibody) excited by ultraviolet light.