Fluorescence discrimination power

In the first attempts to overcome the background problem using decay time, the variation of the fluorescence decay time as a function of wavelength across the entire emission profile for a variety of materials have been used (Measures 1985). For a variety of rocks and minerals, it was proved that this information represents a new kind of signature, the so called fluorescence decay spectrum, that possesses considerable discrimination power, being able to characterize the irradiated material with far superior precision than the normal luminescence spectrum (Fig. 7.2). 

Recently, Schalkhammer et al. have discussed the relevance of surface enhanced fluorescence in immunosensing apphcations (surface-enhanced fluoroimmunoas-say, SE-FIA) [322]. The enhancement mechanism was explained by an electrodynamic model and the interaction between metal particle and fluorophore for the excitation and emission process was discussed. It was shown that the discrimination power increased with decreasing quantum efficiency of the fluorophore. This suggested that in SE-FIA a low-quantum efficiency fluorophore needs to be used, as was shown by experiments with model compounds. 

The color of fibers is one of the most significant characteristics in fiber comparison color matching including fluorescence is inevitable for forensic fiber identification. Measurement of the color of fibers is conducted initially by microspectrophotometry. The MSP provides a great increase of discriminating power. Without this instrument, many false positive errors occur in fiber comparison. It is a convenient, nondestructive method that requires only a small amount of sample. Microspectrophotometry enables... 

Supersonic jet spectroscopy (SJ) Method which measures with high discriminating power utilizing laser-induced or lamp-induced fluorescence spectroscopy. 

In atomic fluorescence spectroscopy, an external source is used just as in atomic absorption, as shown in Figure 24-6. Instead of measuring the attenuated source radiant power, however, the radiant power of fluorescence, Pp, is measured, usually at right angles to the source beam. In such experiments, we must avoid or discriminate against scattered source radiation. Atomic fluorescence is often measured at the same wavelength as the source radiation, in which case it is called resonance fluorescence. 

Fluorescence adds a very powerful set of spectroscopic parameters to relate to structure and dynamics. The excitation spectrum (the absorption spectrum which leads to fluorescence at a chosen wavelength) and the fluorescence emission spectrum C m identify and characterize fluorophores in complex mixtures. Time-resolved fluorescence spectra provide greater discrimination by introducing time as another variable. 

Multicomponent analysis using powerful fluorescence lifetime discrimination approaches. 

Over the past decade, ESI-MS analysis of PCR products has become a mature technology for genetic discrimination. The more mainstream technique, real-time PCR, is also a powerful approach that provides a simple yes or no answer, by generation of a fluorescent signal, as to the presence of a... 

---