The Collaborative International Dictionary
fluorescein \fluo`res"ce*in\, fluoresceine \fluo`res"ce*ine\, fluorescein \flu`o*res"ce*["i]n\, n. (Chem.) A yellowish red, crystalline substance, C20H12O5, produced by heating together phthalic anhydride and resorcin; -- so called, from the very brilliant yellowish green fluorescence of its alkaline solutions. It has acid properties, and its salts of the alkalies are known to the trade under the name of uranin.
Syn: fluorescein, fluorescent dye, resorcinolphthalein.
Wiktionary
n. (context chemistry English) Any of a class of yellow xanthene dyes which are visible when highly diluted; used forensically to detect traces of blood, and in analytical chemistry as an indicator in silver nitrate titrations
WordNet
n. a yellow dye that is visible even when highly diluted; used as an absorption indicator when silver nitrate solution is added to sodium chloride in order to precipitate silver chloride (turns pink when no chloride ions are left in solution and negative fluorescein ions are then absorbed) [syn: fluoresceine, fluorescent dye, resorcinolphthalein]
Wikipedia
Fluorescein ( or ) is a synthetic organic compound available as a dark orange/red powder slightly soluble in water and alcohol. It is widely used as a fluorescent tracer for many applications.
Fluorescein is a fluorophore commonly used in microscopy, in a type of dye laser as the gain medium, in forensics and serology to detect latent blood stains, and in dye tracing. Fluorescein has an absorption maximum at 494 nm and emission maximum of 512 nm (in water). The major derivatives are fluorescein isothiocyanate ( FITC) and, in oligonucleotide synthesis, 6-FAM phosphoramidite.
Fluorescein also has an isosbestic point (equal absorption for all pH values) at 460 nm. Fluorescein is also known as a color additive ( D&C Yellow no. 7). The disodium salt form of fluorescein is known as uranine or D&C Yellow no. 8.
The color of its aqueous solution varies from green to orange as a function of the way it is observed: by reflection or by transmission, as can be noticed in bubble levels, for example; in which fluorescein is added as a colorant to the alcohol filling the tube in order to increase the visibility of the air bubble contained within (thus enhancing the precision of the instrument). More concentrated solutions of fluorescein can even appear red.
Usage examples of "fluorescein".
He scattered Fluorescein Yellow with Optical Brightener into the water.
The ultraviolet-lamp filter was a common one treated with oxide of nickel, and the buttons were an improved alkaline salt of fluorescein coupled with anthracene.
But if you know what you're looking for, like tetrodotoxin, say, because the deceased dropped dead at a sushi party, then there are some monoclonal antibodies tagged with either fluorescein or a radioactive marker that can pick the stuff up.