Rhodamine B is a chemical compound and a

dye Juan de Guillebon, better known by his stage name DyE, is a French musician. He is known for the music video of the single "Fantasy Fantasy is a genre of speculative fiction that involves supernatural or Magic (supernatural), magical ele ...

. It is often used as a

tracer dye Dye tracing is a method of tracking and tracing various Fluid dynamics, flows using dye as a flow tracer when added to a liquid. Dye tracing may be used to analyse the flow of the liquid or the transport of objects within the liquid. Dye tracking m ...

within water to determine the rate and direction of flow and transport.

Rhodamine Rhodamine is a family of related dyes, a subset of the triarylmethane dyes. They are derivatives of xanthene. Important members of the rhodamine family are rhodamine 6G, Rhodamin WT, Texas Red (Sulforhodamin 101), rhodamine 123, and rhod ...

dyes

fluoresce Fluorescence is one of two kinds of photoluminescence, the emission of light by a substance that has absorbed light or other electromagnetic radiation. When exposed to ultraviolet radiation, many substances will glow (fluoresce) with color ...

and can thus be detected easily and inexpensively with

fluorometer A fluorometer, fluorimeter or fluormeter is a device used to measure parameters of visible spectrum fluorescence: its intensity and wavelength distribution of emission spectrum after excitation by a certain spectrum of light. These parameters ...

s. Rhodamine B is used in biology as a

staining Staining is a technique used to enhance contrast in samples, generally at the Microscope, microscopic level. Stains and dyes are frequently used in histology (microscopic study of biological tissue (biology), tissues), in cytology (microscopic ...

fluorescent dye, sometimes in combination with

auramine O Auramine O is a diarylmethane dye used as a fluorescent stain. In its pure form, Auramine O appears as yellow needle crystals. It is insoluble in water and soluble in ethanol and DMSO. Auramine O can be used to stain acid-fast bacteria (e.g. ''M ...

, as the auramine-rhodamine stain to demonstrate

acid-fast Acid-fastness is a physical property of certain bacterial and eukaryotic cells, as well as some sub-cellular structures, specifically their resistance to decolorization by acids during laboratory staining procedures. Once stained as part of a sa ...

organisms, notably ''

Mycobacterium ''Mycobacterium'' is a genus of over 190 species in the phylum Actinomycetota, assigned its own family, Mycobacteriaceae. This genus includes pathogens known to cause serious diseases in mammals, including tuberculosis (''Mycobacterium tuberculo ...

''. Rhodamine dyes are also used extensively in biotechnology applications such as

fluorescence microscopy A fluorescence microscope is an optical microscope that uses fluorescence instead of, or in addition to, scattering, reflection, and attenuation or absorption, to study the properties of organic or inorganic substances. A fluorescence micro ...

flow cytometry Flow cytometry (FC) is a technique used to detect and measure the physical and chemical characteristics of a population of cells or particles. In this process, a sample containing cells or particles is suspended in a fluid and injected into the ...

fluorescence correlation spectroscopy 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 ...

and

ELISA The enzyme-linked immunosorbent assay (ELISA) (, ) is a commonly used analytical biochemistry assay, first described by Eva Engvall and Peter Perlmann in 1971. The assay is a solid-phase type of enzyme immunoassay (EIA) to detect the presence of ...

Other uses

Rhodamine B is often mixed with herbicides to show where they have been used. It is also being tested for use as a

biomarker In biomedical contexts, a biomarker, or biological marker, is a measurable indicator of some biological state or condition. Biomarkers are often measured and evaluated using blood, urine, or soft tissues to examine normal biological processes, ...

in oral

rabies Rabies is a viral disease that causes encephalitis in humans and other mammals. It was historically referred to as hydrophobia ("fear of water") because its victims panic when offered liquids to drink. Early symptoms can include fever and abn ...

vaccines A vaccine is a biological preparation that provides active acquired immunity to a particular infectious or malignant disease. The safety and effectiveness of vaccines has been widely studied and verified. A vaccine typically contains an ag ...

for

wildlife Wildlife refers to domestication, undomesticated animals and uncultivated plant species which can exist in their natural habitat, but has come to include all organisms that grow or live wilderness, wild in an area without being species, introdu ...

, such as

raccoon The raccoon ( or , ''Procyon lotor''), sometimes called the North American, northern or common raccoon (also spelled racoon) to distinguish it from Procyonina, other species of raccoon, is a mammal native to North America. It is the largest ...

s, to identify animals that have eaten a vaccine

bait Bait may refer to: General * Bait (luring substance), bait as a luring substance ** Fishing bait, bait used for fishing Film * ''Bait'' (1950 film), a British crime film by Frank Richardson * ''Bait'' (1954 film), an American noir film by Hugo ...

. The rhodamine is incorporated into the animal's

whiskers Whiskers, also known as vibrissae (; vibrissa; ) are a type of stiff, functional hair used by most therian mammals to sense their environment. These hairs are finely specialised for this purpose, whereas other types of hair are coarser as ta ...

and

teeth A tooth (: teeth) is a hard, calcified structure found in the jaws (or mouths) of many vertebrates and used to break down food. Some animals, particularly carnivores and omnivores, also use teeth to help with capturing or wounding prey, tear ...

. 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. Rhodamine B (BV10) is mixed with quinacridone magenta (PR122) to make the bright pink watercolor known as Opera Rose.

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. The fluorescence intensity of rhodamine B will decrease as temperature increases. The solubility of rhodamine B in water varies by manufacturer, and has been reported as 8 g/L and ~15 g/L, while solubility in alcohol (presumably

ethanol Ethanol (also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an organic compound with the chemical formula . It is an Alcohol (chemistry), alcohol, with its formula also written as , or EtOH, where Et is the ps ...

) has been reported as 15 g/L. Chlorinated tap water decomposes rhodamine B. Rhodamine B solutions adsorb to plastics and should be kept in glass. Rhodamine B is tunable around 610 nm when used as a

laser dye file:Coherent 899 dye laser.jpg, Close-up of a table-top dye laser using Rhodamine 6G as active medium. file:rhodamine 6G.svg, Molecular structure of Rhodamine 6G, perhaps the best known laser dye. A Laser dye is a dye used as laser medium in a dy ...

. Its luminescence

quantum yield In particle physics, the quantum yield (denoted ) of a radiation-induced process is the number of times a specific event occurs per photon absorbed by the system. \Phi(\lambda)=\frac Applications Fluorescence spectroscopy The fluorescence ...

is 0.65 in basic

, 0.49 in ethanol, 1.0, and 0.68 in 94% ethanol. The fluorescence yield is temperature dependent; the compound is

fluxional In chemistry and molecular physics, fluxional (or non-rigid) molecules are molecules that undergo dynamics such that some or all of their atoms interchange between symmetry-equivalent positions. Because virtually all molecules are fluxional in som ...

in that its excitability is in

thermal equilibrium Two physical systems are in thermal equilibrium if there is no net flow of thermal energy between them when they are connected by a path permeable to heat. Thermal equilibrium obeys the zeroth law of thermodynamics. A system is said to be in t ...

at room temperature.

Safety and health

In California, rhodamine B is suspected to be carcinogenic and thus products containing it must contain a warning on its label. Cases of economically motivated adulteration, where it has been illegally used to impart a red color to

chili powder Chili powder (also spelled chile, chilli, or, alternatively, powdered chili) is the dried, pulverized fruit of one or more varieties of chili pepper, sometimes with the addition of other spices (in which case it is also sometimes known as chili p ...

, have come to the attention of food safety regulators.

References

Notes

{{Stains Microscopy Microbiology techniques Laboratory techniques Histopathology Histotechnology Staining dyes Staining * Laser gain media Benzoic acids Aromatic amines Chlorides Quaternary ammonium compounds Triarylmethane dyes Xanthenes Diethylamino compounds Fluorescent dyes

Other uses

Properties

Safety and health

See also

References

Notes