Molecular Fluorescence in Analytical Chemistry

The monochromators are used to select the appropriate wavelengths for excitation and emission. The detector is placed at right angles to the incident light path, so that fluorescence, which is emitted in all directions, falls on the detector but no incident light is detected. 

Numerous examples of the direct determination of compounds by fluorimetry have been reported in the literature. For example, the urine of patients with kidney disorders contains abnormally high levels of the 

Fluorescence quantum yields determined in solid solu- 

However, most molecules and ions show no fluorescence and so it is necessary to resort to other methods in these cases. Derivatisation methods can be used where the substance of interest is not fluorescent but may be converted into a fluorescent derivative by reaction with a suitable (nonfluorescent) reagent. 

Quenching methods, in which the fluorescence of a substance is reduced by the quenching action of an analyte, can also be used in fluorescence analysis. Such methods are particularly well suited to the analysis of gases. 

---