Quenching
- Quenching
is the reduction in the intensity of
fluorescence due to specific effects of constituents of the solution itself.
It may be
caused in several ways:
- Concentration
quenching: excessive absorption of either primary or fluorescent radiation by
the solution. Also called Inner Filter effect.
- If it
occurs as a result of absorption of absorption of the fluorescent substance
itself, the phenomenon is called as self-quenching.
- Quenching
occurs as a result of reduction in emission due to actual changes in the
chemical nature of the fluorescent substance is called as chemical quenching
-
E.g.,
aniline, when excited at 290 nm, shows a blue fluorescence between pH 5 to 13.
But at low pH, aniline exists as the anilinium cation and at basic pH anion and
both don’t fluoresce.
In the pharmaceutical sector, quenching plays a critical role in analytical procedures. Quenching involves the reduction in fluorescence intensity due to solution constituents. Concentration quenching, known as the Inner Filter Effect, can affect accurate fluorescent measurements in drug formulations. Self-quenching, where a substance absorbs its own fluorescence, is a unique challenge. Additionally, chemical quenching, driven by changes in a compound's chemical nature, impacts drug stability and interactions. Understanding quenching phenomena is vital in pharmaceutical research to ensure precise analytical techniques and the efficacy of drug formulations.
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