Fluorescence and phosphorescence spectroscopy

The most popular light sources in modern fluoremeters are gas lasers. At the present time, nitrogen, XeCl, XeF and KrF are used quite frequently for fluoremetry. The reason to use lasers as the light source for fluoremetry is the same as was given for Raman spectroscopy lasers emit monochromic light with very high intensity in comparison to the classical light sources. 

Marcel Dekker, Inc. 270 Madison Avenue, New York, New York 10016 

Almost exclusively, only diffraction grids are used as monochromators in fluoremeters. The functioning principle of this device was described in detail in the section in this chapter devoted to infrared spectroscopy. 

The evaluation of the results of fluoremetry can be done both quantitatively and qualitatively. Qualitative evaluation is done in the same way as for most spectral methods. There are tables of spectra of known compounds or the spectra are saved in digital libraries, which are delivered together with the instrument. There are three methods used for quantitative evaluation  

converting of non-fluorescence-able samples into fluorescence-able samples 

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Figure 5.7 Layout of a typical fluorescence spectrometer. After Rendell [132]. Reprinted from D. Rendell, Fluorescence and Phosphorescence Spectroscopy. Copyright 1987 John Wiley Sons, Limited. Reproduced with permission...

D. Rendell, Fluorescence and Phosphorescence Spectroscopy, John Wiley Sons, Ltd, Chichester (1987). 

The fractions from elution chromatography were studied by a number of spectroscopic methods, n.m.r., i.r., u.v., fluorescence and phosphorescence spectroscopy. Equivalent fractions from chromatographic separation of the various oils showed no significant differences in their spectra and it appears that the composition of the fractions was independent of the catalyst concentration used to produce the oil. Though, as previously mentioned the amounts of the various fractions especially the polar fractions differ with the catalyst concentration. G.1.C. analysis of the saturate fractions also indicated no changes with different catalyst concentrations. 

SG Schulman. Fluorescence and Phosphorescence Spectroscopy, Physiochemical Principle and Practice. London Pergamon Press, 1977. 

Schulman S. G. (1977) Fluorescence and Phosphorescence Spectroscopy Physicochemical Principles and Practice, Pergamon Press, Oxford. 

When the sample is stimulated hy application of an external electromagnetic radiation source, several processes are possible. For example, the radiation can be scattered or reflected. What is important to us is that some of the incident radiation can be absorbed and thus promote some of the analyte species to an excited state, as shown in Figure 24-5. In absorption spectroscopy, we measure the amount of light absorbed as a function of wavelength. This can give both qualitative and quantitative information about the sample. In photoluminescence spectroscopy (Figure 24-6), the emission of photons is measured after absorption. The most important forms of photoluminescence for analytical purposes are fluorescence and phosphorescence spectroscopy. 

UV/VIS spectroscopy is a playground for spectroscopists. Neunhoeffer cited a number of leading references. This may be continued with a number of publications dealing with absorption, fluorescence, and phosphorescence spectroscopy as well as vibrational fine structure of the ground state and excited electronic states. 

Electronic (absorption and emission) spectroscopies are among the most widely applied experimental techniques in supramolecular chemistry [1]. This section provides a condensed overview of the principles and uses of UV-Vis absorption and emission (fluorescence and phosphorescence) spectroscopies in the study of cydodextrin (CyD) indusion complexes. The emphasis will be on a presentation of the main effects of complex formation on measured spectra, quantum yields, and kinetics. This latter point will be treated in a separate section as it exemplifies the power of spectroscopic techniques in supramolecular studies. Only nonderiva-tized CyDs will be discussed. This is not a comprehensive review, cited references, taken from the literature of the literature of the past ten years, are mainly intended to provide illustrative examples. 

The most investigated thioketones have found applications in the pharmaceutical, polymer, pesticide, and herbicide industries. However, there is increasing interest in their photophysic and non-linear electric properties, which make them interesting molecules for fluorescence and phosphorescence spectroscopy, and promising building blocks for non-linear optical materials. Studies concerning the addition of a hydrogen atom to C=S, the environment" and the C NMR for thioketones and selenoketones have been also carried out. 

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