Difference between revisions of "Fluorescein"
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| − | '''Fluorescein''' (also known as '''resorcinophthalein''' or D&C yellow no. 7) is an organic compound that is a brick-red solid at room temperature. It dissolves slightly in water to give bright yellow, strongly fluorescent solutions. '''Sodium fluorescein''', also known as '''uranine''', has a much higher solubility in water. | + | '''Fluorescein''' (also known as '''resorcinophthalein''' or '''D&C yellow no. 7''') is an organic compound that is a brick-red solid at room temperature. It dissolves slightly in water to give bright yellow, strongly fluorescent solutions. '''Sodium fluorescein''', also known as '''uranine''', has a much higher solubility in water. |
| − | + | Despite its name, fluorescein is NOT a [[fluorine]] compound. | |
| + | ==Properties== | ||
| + | ===Chemical=== | ||
| + | Fluorescein will react with bicarbonates to form fluorescein salts. | ||
| + | |||
| + | ===Physical=== | ||
| + | Fluorescein is a dark red powder, slightly soluble in water. | ||
| + | |||
| + | ====Fluorescence==== | ||
Fluorescein has an absorption peak at 494 nm and an emission peak at 512 nm. Its isosbestic point (wavelength that is equally absorbed at all pH values) is 464 nm. | Fluorescein has an absorption peak at 494 nm and an emission peak at 512 nm. Its isosbestic point (wavelength that is equally absorbed at all pH values) is 464 nm. | ||
| − | == | + | ==Availability== |
| + | Fluorescein is sold by chemical suppliers. It can also be found on eBay and Amazon, at various prices. | ||
| + | [http://www.ebay.com/itm/100g-Fluorescein-powder-fluorescent-dye-water-tracing/130762418577 One seller] offers 100 g of fluorescein at $18.81. | ||
| + | |||
| + | ==Obtaining== | ||
===Extraction=== | ===Extraction=== | ||
Certain brands of highlighters use a solution of fluorescein in water with a water-soluble binder. The ink cartridges of these highlighters may be extracted with [[isopropanol]] to give a solution of pure fluorescein. Some highlighters use [[pyranine]] instead, which has a strong blue fluorescence at high pH. | Certain brands of highlighters use a solution of fluorescein in water with a water-soluble binder. The ink cartridges of these highlighters may be extracted with [[isopropanol]] to give a solution of pure fluorescein. Some highlighters use [[pyranine]] instead, which has a strong blue fluorescence at high pH. | ||
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Fluorescein is easily prepared from [[resorcinol]] and [[phthalic anhydride]] through a [[Friedel-Crafts]] reaction with an acid catalyst, most often concentrated [[sulfuric acid.]] The product may be diluted into a basic solution to obtain a dark sodium fluorescein stock solution, which works for most demonstrations. | Fluorescein is easily prepared from [[resorcinol]] and [[phthalic anhydride]] through a [[Friedel-Crafts]] reaction with an acid catalyst, most often concentrated [[sulfuric acid.]] The product may be diluted into a basic solution to obtain a dark sodium fluorescein stock solution, which works for most demonstrations. | ||
| − | == | + | ==Projects== |
| + | ==See also== | ||
* [[Rhodamine]] | * [[Rhodamine]] | ||
* [[Eosin Y]] | * [[Eosin Y]] | ||
| + | |||
| + | ==Handling== | ||
| + | ===Safety=== | ||
| + | |||
| + | ===Storage=== | ||
| + | |||
| + | ===Disposal=== | ||
| + | |||
| + | ==References== | ||
| + | <references/> | ||
| + | ===Relevant Sciencemadness threads=== | ||
| + | |||
| + | [[Category:Chemical compounds]] | ||
| + | [[Category:Organic compounds]] | ||
| + | [[Category:Phenols]] | ||
| + | [[Category:Dyes]] | ||
| + | [[Category:Fluorescent dyes]] | ||
| + | [[Category:Fluorescent materials]] | ||
Revision as of 13:45, 7 February 2016
| Names | |
|---|---|
| Systematic IUPAC name
3',6'-Dihydroxy-3H-spiro[2-benzofuran-1,9'-xanthen]-3-one | |
| Other names
Fluorescein, Resorcinolphthalein, diresorcinolphthalein, D&C yellow no. 7, Japan yellow 201, soap yellow
| |
| Properties | |
| C20H12O5 | |
| Molar mass | 332.31 |
| Appearance | Dark red powder |
| Density | 1.602 |
| Melting point | 314 to 316 °C (597 to 601 °F; 587 to 589 K) |
| Soluble in basic aqueous solutions, acetone and diethyl ether, slightly soluble in water | |
| Acidity (pKa) | 6.4 |
| Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |
| Infobox references | |
Fluorescein (also known as resorcinophthalein or D&C yellow no. 7) is an organic compound that is a brick-red solid at room temperature. It dissolves slightly in water to give bright yellow, strongly fluorescent solutions. Sodium fluorescein, also known as uranine, has a much higher solubility in water.
Despite its name, fluorescein is NOT a fluorine compound.
Contents
Properties
Chemical
Fluorescein will react with bicarbonates to form fluorescein salts.
Physical
Fluorescein is a dark red powder, slightly soluble in water.
Fluorescence
Fluorescein has an absorption peak at 494 nm and an emission peak at 512 nm. Its isosbestic point (wavelength that is equally absorbed at all pH values) is 464 nm.
Availability
Fluorescein is sold by chemical suppliers. It can also be found on eBay and Amazon, at various prices.
One seller offers 100 g of fluorescein at $18.81.
Obtaining
Extraction
Certain brands of highlighters use a solution of fluorescein in water with a water-soluble binder. The ink cartridges of these highlighters may be extracted with isopropanol to give a solution of pure fluorescein. Some highlighters use pyranine instead, which has a strong blue fluorescence at high pH.
Bubble levels are often very dilute fluorescein solutions.
Synthesis
Fluorescein is easily prepared from resorcinol and phthalic anhydride through a Friedel-Crafts reaction with an acid catalyst, most often concentrated sulfuric acid. The product may be diluted into a basic solution to obtain a dark sodium fluorescein stock solution, which works for most demonstrations.
