Uranine

Fluorescein

Names
Pronunciation	/fluːˈrɛsiᵻn/ or /fluːˈrɛsiːn/
IUPAC name 3′,6′-dihydroxyspiro[isobenzofuran-1(3H),9′-[9H]xanthen]-3-one
Other names Fluorescein, resorcinolphthalein, C.I. 45350, solvent yellow 94, D & C yellow no. 7, angiofluor, Japan yellow 201, soap yellow
Identifiers
CAS Number	2321-07-5 Y
3D model (Jmol)	Interactive image
ChEBI	CHEBI:31624 Y
ChEMBL	ChEMBL177756 N
ChemSpider	15968 Y
DrugBank	DB00693 Y
ECHA InfoCard	100.017.302
EC Number	219-031-8
KEGG	D01261 Y
MeSH	Fluorescein
PubChem	16850
UNII	TPY09G7XIR Y
InChI InChI=1S/C20H12O5/c21-11-5-7-15-17(9-11)24-18-10-12(22)6-8-16(18)20(15)14-4-2-1-3-13(14)19(23)25-20/h1-10,21-22H Y Key: GNBHRKFJIUUOQI-UHFFFAOYSA-N Y InChI=1/C20H12O5/c21-11-5-7-15-17(9-11)24-18-10-12(22)6-8-16(18)20(15)14-4-2-1-3-13(14)19(23)25-20/h1-10,21-22H Key: GNBHRKFJIUUOQI-UHFFFAOYAZ
SMILES c1ccc2c(c1)C(=O)OC23c4ccc(cc4Oc5c3ccc(c5)O)O
Properties
Chemical formula	C20H12O5
Molar mass	332.31 g·mol−1
Density	1.602 g/mL
Melting point	314 to 316 °C (597 to 601 °F; 587 to 589 K)
Solubility in water	Slightly
Pharmacology
ATC code	S01JA01 (WHO)
Hazards
GHS pictograms
GHS signal word	Warning
GHS hazard statements	H319
GHS precautionary statements	P305, P351, P338
S-phrases	S26 S36
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N  (what is YN ?)
Infobox references

Fluorescein is a manufactured organic compound and dye. It is 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.

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.

It is on the World Health Organization's List of Essential Medicines, the most important medications needed in a basic health system.