Quantitative Applications Using Molecular Luminescence

Molecular fluorescence and, to a lesser extent, phosphorescence have been used for the direct or indirect quantitative analysis of analytes in a variety of matrices. A direct quantitative analysis is feasible when the analyte s quantum yield for fluorescence or phosphorescence is favorable. When the analyte is not fluorescent or phosphorescent or when the quantum yield for fluorescence or phosphorescence is unfavorable, an indirect analysis may be feasible. One approach to an indirect analysis is to react the analyte with a reagent, forming a product with fluorescent properties. Another approach is to measure a decrease in fluorescence when the analyte is added to a solution containing a fluorescent molecule. A decrease in fluorescence is observed when the reaction between the analyte and the fluorescent species enhances radiationless deactivation, or produces a nonfluorescent product. The application of fluorescence and phosphorescence to inorganic and organic analytes is considered in this section. 

Organic Analytes As noted earlier, organic compounds containing aromatic rings generally are fluorescent, but aromatic heterocycles are often phosphorescent. Many important biochemical, pharmaceutical, and environmental compounds are aromatic and, therefore, can be analyzed quantitatively by fluorometry 

Structure of (a) alizarin garnet R, and (b) its metal-ligand complex with AP+. 

Selected Chelating Agents for the Fluorometric Analysis of Inorganic Metal Ions 

Selected Examples of Organic Compounds of Biochemical, Pharmaceutical, and Environmental Significance That Show Natural Fluorescence or t Phosphorescence 

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