Rhodamine B
Chemical compound
From Wikipedia, the free encyclopedia
Rhodamine B /ˈroʊdəmiːn/ is a chemical compound and a dye. It is often used as a tracer dye within water to determine the rate and direction of flow and transport. Rhodamine dyes fluoresce and can thus be detected easily and inexpensively with fluorometers.
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| Names | |
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| Preferred IUPAC name
9-(2-Carboxyphenyl)-6-(diethylamino)-N,N-diethyl-3H-xanthen-3-iminium chloride | |
| Other names
Rhodamine 610, C.I. Pigment Violet 1, Basic Violet 10, C.I. 45170 | |
| Identifiers | |
3D model (JSmol) |
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| ChEBI | |
| ChEMBL | |
| ChemSpider | |
| ECHA InfoCard | 100.001.259 |
| KEGG | |
PubChem CID |
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| UNII | |
CompTox Dashboard (EPA) |
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| Properties | |
| C28H31ClN2O3 | |
| Molar mass | 479.02 |
| Appearance | Green powder[1] |
| Melting point | 210 to 211 °C (410 to 412 °F; 483 to 484 K) (Decomposes) |
| 8 to 15 g/L (20 °C)[2][nt 1] | |
| Hazards | |
| Safety data sheet (SDS) | MSDS |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Rhodamine B is used in biology as a staining fluorescent dye, sometimes in combination with auramine O, as the auramine-rhodamine stain to demonstrate acid-fast organisms, notably Mycobacterium. Rhodamine dyes are also used extensively in biotechnology applications such as fluorescence microscopy, flow cytometry, fluorescence correlation spectroscopy and ELISA.[citation needed]
Other uses
Rhodamine B is often mixed with herbicides to show where they have been used.[3]
It is also being tested for use as a biomarker in oral rabies vaccines for wildlife, such as raccoons, to identify animals that have eaten a vaccine bait. The rhodamine is incorporated into the animal's whiskers and teeth.[4] Rhodamine B is an important hydrophilic xanthene dye well known for its stability and is widely used in the textile industry, leather, paper printing, paint, coloured glass and plastic industries.[5]
Rhodamine B (BV10) is mixed with quinacridone magenta (PR122) to make the bright pink watercolor known as Opera Rose.[6]
Properties
Rhodamine B can exist in equilibrium between two forms: an "open"/fluorescent form and a "closed"/nonfluorescent spirolactone form. The "open" form dominates in acidic condition while the "closed" form is colorless in basic condition.[7]
The fluorescence intensity of rhodamine B will decrease as temperature increases.[8]
The solubility of rhodamine B in water varies by manufacturer, and has been reported as 8 g/L and ~15 g/L,[2] while solubility in alcohol (presumably ethanol) has been reported as 15 g/L.[nt 1] Chlorinated tap water decomposes rhodamine B. Rhodamine B solutions adsorb to plastics and should be kept in glass.[9] Rhodamine B is tunable around 610 nm when used as a laser dye.[10] Its luminescence quantum yield is 0.65 in basic ethanol,[11] 0.49 in ethanol,[12] 1.0,[13] and 0.68 in 94% ethanol.[14] The fluorescence yield is temperature dependent;[15] the compound is fluxional in that its excitability is in thermal equilibrium at room temperature.[16]
Safety and health
In California, rhodamine B is suspected to be carcinogenic and thus products containing it must contain a warning on its label.[17] Cases of economically motivated adulteration, where it has been illegally used to impart a red color to chili powder, have come to the attention of food safety regulators.[18]