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Fluorescence in the life sciences is used generally as a non-destructive way of tracking or analysis of biological molecules by means of the fluorescent emission at a specific frequency where there is no background from the excitation light, as relatively few cellular components are naturally fluorescent (called intrinsic or autofluorescence).
A simplified Jablonski diagram illustrating the change of energy levels.. The principle behind fluorescence is that the fluorescent moiety contains electrons which can absorb a photon and briefly enter an excited state before either dispersing the energy non-radiatively or emitting it as a photon, but with a lower energy, i.e., at a longer wavelength (wavelength and energy are inversely ...
Micrograph of paper autofluorescing under ultraviolet illumination. The individual fibres in this sample are around 10 μm in diameter.. Autofluorescence is the natural fluorescence of biological structures such as mitochondria and lysosomes, in contrast to fluorescence originating from artificially added fluorescent markers (fluorophores).
Atomic Fluorescence Spectroscopy (AFS) techniques are useful in other kinds of analysis/measurement of a compound present in air or water, or other media, such as CVAFS which is used for heavy metals detection, such as mercury. Fluorescence can also be used to redirect photons, see fluorescent solar collector.
Phosphorescence is a type of photoluminescence related to fluorescence. When exposed to light (radiation) of a shorter wavelength, a phosphorescent substance will glow, absorbing the light and reemitting it at a longer wavelength. Unlike fluorescence, a phosphorescent material does not immediately reemit the radiation it absorbs.
Biofluorescence is frequent in plants, and can occur in many of their parts. [4] The biofluorescence in chlorophyll but has been studied since the 1800s. [5] Generally, chlorophyll fluoresces red, [6] and can be used as a measure of photosynthetic capabilities, [7] [6] or general health. [5]
Other problems that may arise when using immunofluorescence techniques include autofluorescence, spectral overlap and non-specific staining. [1] [2] Autofluorescence includes the natural fluorescence emitted from the sample tissue or cell itself. Spectral overlap happens when a fluorophore has a broad emission specter, that overlaps with the ...
It is neither fluorescence not phosphorescence. [ 2 ] [ 3 ] In fluorescence, the lifetime of the excited state lasts a few nanoseconds. In phosphorescence, even if the emission lives several seconds, this is due to deexcitation between two electronic states of different spin multiplicity .