Quenching (fluorescence)

Overview

 * For other uses, see Quenching (disambiguation).

Quenching refers to any process which decreases the fluorescence intensity of a given substance. A variety of processes can result in quenching, such as excited state reactions, energy transfer, complex-formation and collisional quenching. As a consequence, quenching is often heavily dependent on pressure and temperature. Molecular oxygen and the iodide ion are common chemical quenchers. Quenching poses a problem for non-instant spectroscopic methods, such as laser-induced fluorescence.

Quenching is made use of in optode sensors; for instance the quenching effect of oxygen on certain rubidium complexes allows the measurement of oxygen saturation in solution. Quenching and dequenching upon interaction with a specific molecular biological target is the basis for activatable optical contrast agents for molecular imaging.