What Is Fluorescein?
Fluorescein, with the chemical formula C20H12O5 and a molecular weight of 332.31, is a yellowish-red powder. Synthesized by Adolph von Beyer in 1871, it’s insoluble in water and slightly soluble in ethanol. This fluorescent dye is known for its bright green fluorescence, making it a valuable tool in various fields.
Uses of Fluorescein
- Bioscience: Used in fluorescence microscopy and cell biology to track the position and movement of objects.
- Medical Diagnostics: Helps detect pathogens and genetic mutations, and is used in angiography in ophthalmology.
- Analytical Chemistry: Employed as chemical sensors and in detecting ammonia in water sources.
Properties of Fluorescein
Fluorescein is highly sensitive to light, with its fluorescence intensity being highest in the pH range of 7-9. It’s stable to acids and bases but degrades under prolonged light exposure, requiring light shielding during use and storage.
Structure of Fluorescein
Fluorescein, a xanthene skeleton-based organic compound, exhibits unique optical properties due to its conjugated pi-electron system. It contains hydroxyl groups at the 3- and 6-positions, influencing its water solubility and pH-dependent fluorescence intensity changes.
Other Information on Fluorescein
How Fluorescein Is Produced
Fluorescein synthesis involves reactions like the Friedel-Crafts reaction, using phthalin and resorcinol, and the Wittig Reaction with iodomethane and triphenylphosphine.