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Fluorescence spectroscopy (also known as fluorimetry or spectrofluorometry) is a type of electromagnetic spectroscopy that analyzes fluorescence from a sample. It involves using a beam of light, usually ultraviolet light , that excites the electrons in molecules of certain compounds and causes them to emit light; typically, but not necessarily ...
Fluorescence anisotropy or fluorescence polarization is the phenomenon where the light emitted by a fluorophore has unequal intensities along different axes of polarization. Early pioneers in the field include Aleksander Jablonski , Gregorio Weber , [ 1 ] and Andreas Albrecht. [ 2 ]
Processes such as fluorescence and phosphorescence are examples of intramolecular deactivation processes. An intermolecular deactivation is where the presence of another chemical species can accelerate the decay rate of a chemical in its excited state. In general, this process can be represented by a simple equation:
The modulation of the fluorescence of the biological sample provides a better understanding of the complex system. TCSPC is widely used to study the intensity decay of Green Fluorescent Proteins (GFP), Chlorophyll aggregates in hexane, [27] single fluorescence amino acid-containing proteins, and dinucleotides (FAD). [28]
In chemistry, solvatochromism is the phenomenon observed when the colour of a solution is different when the solute is dissolved in different solvents. [1] [2] Reichardt's dye dissolved in different solvents. The solvatochromic effect is the way the spectrum of a substance (the solute) varies when the substance is dissolved in a variety of ...
Time-resolved fluorescence (TRF) measurement is very similar to fluorescence intensity (FI) measurement. The only difference is the timing of the excitation/measurement process. When measuring FI, the excitation and emission processes are simultaneous: the light emitted by the sample is measured while excitation is taking place.
Fluorescence correlation spectroscopy (FCS) is a statistical analysis, via time correlation, of stationary fluctuations of the fluorescence intensity. Its theoretical underpinning originated from L. Onsager's regression hypothesis. The analysis provides kinetic parameters of the physical processes underlying the fluctuations.
The fluorescence is (a.) demodulated and (b.) phase shifted; both quantities are related to the characteristic decay times of the fluorophore. Also, y-components to the excitation and fluorescence sine waves will be modulated, and lifetime can be determined from the modulation ratio of these y-components.