Fluorescent optical chemical sensors fluorescence quenching

Optical sensors for oxygen measurement are attractive since they can be fast, do not consume oxygen and are not easily poisoned. The most common method adopted in construction is based on quenching of fluorescence from appropriate chemical species. The variation in fluorescence signal (I), or fluorescence decay time (x) with oxygen concentration [O2] is described by Stem-Volmer equation91 ... 

While there are only a few examples that can be used for direct detection of desired analytes, many simple molecules and ions do not have optical activity under regular conditions, a chemical reaction is needed to generate an optically active species. The reactions can be acid-base, ion pairing, complexation reactions, or quenching of fluorescence by 02, paramagnetic molecules, etc. Optical sensors for a few analyte or group analytes are summarized below. 

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