Pyranine

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Pyranine
Pyranine fluorescence vials by Brain&Force.jpg
Pyranine fluoresces green in neutral conditions and blue in acidic conditions (left to right).
Names
IUPAC name
Trisodium 8-hydroxypyrene-1,3,6-trisulfonate
Other names
8-Hydroxypyrene-1,3,6-trisulfonic acid, Na3 salt
HPTS
Solvent Green 7
Sulfonated hydroxy pyrene trisodium salt
Properties
C16H7Na3O10S3
Molar mass 524.37
Appearance Yellow-green crystalline powder
Melting point 300 °C (572 °F; 573 K) (decomposition)
Boiling point Decomposes
Soluble
Hazards
Safety data sheet Sigma-Aldrich
Lethal dose or concentration (LD, LC):
1,060 mg/kg (mouse, IV)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Pyranine is a yellow arylsulfonate dye, commonly found in highlighters, that exhibits strong fluorescence.

Properties

Chemical

The fluorescence of depends on the pH of the solution, which makes it a fluorescent pH indicator. At low pH levels, the color of its fluorescence changes from green to blue. It also acts as a regular pH indicator, and turns from yellow to colorless at the same low pH levels.

Physical

Pyranine is highly soluble in water.

Acquisition

Relatively pure pyranine can be found in highlighters and used as a pH indicator.

Preparation

Pyranine can be prepared by refluxing an aqueous solution of sodium hydroxide and pyrenetetrasulfonic acid. Pyranine crystallizes as yellow needles when adding an aqueous solution of sodium chloride.[1]

Projects

  • "Radioactive" color-changing baking soda volcano
  • Lava lamp

Handling

Safety

Pyranine has low toxicity.

Storage

It should be stored in closed containers.

Disposal

Pyranine can be safely poured down the drain.

See also

References

  1. http://onlinelibrary.wiley.com/doi/10.1002/jlac.19395400113/abstract

Relevant Sciencemadness threads