Fluorescein disodium salt
[CAS# 518-47-8]

Identification

• Classification: API >> Diagnostic medication >> Organ function test agent
• Name: Fluorescein disodium salt
• Synonyms: Acid Yellow 73; C.I. 45350; Disodium 2-(3-oxo-6-oxidoxanthen-9-yl)benzoate; Uranine
• Molecular Formula: C₂₀H₁₂O₅^.₂Na
• Molecular Weight: 376.27
• CAS Registry Number: 518-47-8
• EC Number: 208-253-0
• SMILES: C1=CC=C2C(=C1)C(=O)OC23C4=C(C=C(C=C4)[O-])OC5=C3C=CC(=C5)[O-].[Na+].[Na+]

Properties

• Melting point: 320 ºC
• Water solubility: 500 g/L (20 ºC)

Safety Data

• Hazard Symbols: GHS07 Warning
• Hazard Statements: H319
• Precautionary Statements: P280-P305+P351+P338

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Eye irritation	Eye Irrit.	2	H319
Skin irritation	Skin Irrit.	2	H315
Acute toxicity	Acute Tox.	4	H332
Acute toxicity	Acute Tox.	4	H312
Germ cell mutagenicity	Muta.	1A	H340
Skin sensitization	Skin Sens.	1	H317

Discovory and Applicatios

Fluorescein disodium salt is a water-soluble, organic compound that belongs to the class of fluorescein dyes. It is widely used in various applications, ranging from biological and chemical research to industrial processes. The disodium salt form of fluorescein is particularly notable for its high solubility in water, which makes it suitable for use in aqueous environments, including biological assays, fluorescence microscopy, and flow cytometry.

The discovery of fluorescein dates back to the 19th century, with the first synthesis occurring in 1871 by the German chemist Adolf von Baeyer. Initially, fluorescein was recognized for its ability to fluoresce under ultraviolet light, a property that made it useful for several early investigations into the behavior of light and dyes. However, it wasn't until the 20th century that the full potential of fluorescein as a versatile probe for fluorescence applications became apparent.

Fluorescein disodium salt is derived from fluorescein, which is a derivative of xanthene, and it possesses a characteristic structure that includes a benzene ring fused to a lactone group. In the disodium salt form, two sodium ions are associated with the fluorescein molecule, facilitating its solubility in water and enhancing its compatibility with biological systems. The dye has a strong green fluorescence when exposed to light in the blue to ultraviolet range, which makes it useful for detecting and quantifying specific molecules in both laboratory and clinical settings.

One of the primary applications of fluorescein disodium salt is in fluorescence microscopy, where it is used as a fluorescent tracer to visualize biological samples. The compound's ability to emit intense green fluorescence under UV light allows researchers to tag specific proteins, cells, or tissues, facilitating the study of their structure and function. Fluorescein-labeled antibodies or other biomolecules can be used in conjunction with fluorescence microscopy techniques to track interactions, localization, and dynamic processes in living organisms or cell cultures.

Fluorescein disodium salt is also employed in various diagnostic applications, particularly in ophthalmology. In the form of an eye drop solution, it is used as a diagnostic tool in fluorescein angiography. In this procedure, fluorescein is injected into the bloodstream, and its movement through the blood vessels in the retina is visualized using specialized imaging equipment. This technique is valuable for detecting and monitoring a range of eye conditions, including diabetic retinopathy, age-related macular degeneration, and retinal vein occlusion.

Beyond its medical and biological applications, fluorescein disodium salt is used as a pH indicator and a tracer in environmental studies. In the field of hydrology, it is commonly used to trace the movement of water through soil or groundwater. Its fluorescence allows it to be easily tracked and quantified in water samples, helping researchers study flow patterns and identify contamination sources.

In addition to its role in research and diagnostics, fluorescein disodium salt has several industrial applications. It is used in dyeing processes, particularly for textiles, where it imparts a bright, fluorescent green color. The compound is also found in highlighter pens, where its fluorescent properties make it highly visible under UV light.

Fluorescein disodium salt is generally considered safe when used appropriately, but like any chemical substance, it must be handled with care. In laboratory and medical settings, proper precautions should be taken to avoid direct contact with the eyes and skin, as it may cause irritation. Ingestion or inhalation of large quantities of fluorescein disodium salt can also lead to adverse effects, although such incidents are rare due to its relatively low toxicity. It is essential to follow safety protocols, including the use of gloves, goggles, and lab coats, when working with fluorescein disodium salt.

The compound's environmental impact is minimal, as fluorescein disodium salt is biodegradable and does not accumulate in the environment. However, it should still be disposed of properly to prevent any potential contamination of water systems.

In conclusion, fluorescein disodium salt is a versatile and widely used compound in scientific research, medical diagnostics, and industrial applications. Its fluorescent properties enable its use as a marker in a variety of settings, including biological research, clinical diagnostics, and environmental monitoring. The compound's ability to provide clear, bright fluorescence under UV light has made it an indispensable tool in many fields, and its continued use and development promise further advancements in diagnostic and research technologies.

References

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DOI: 10.1074/jbc.ra119.010201

2020. Cytotoxic Profiling of Annotated and Diverse Chemical Libraries Using Quantitative High-Throughput Screening. SLAS Discovery: Advancing Life Sciences R & D, 25(2).
DOI: 10.1177/2472555219873068

2021. A target-agnostic screen identifies approved drugs to stabilize the endoplasmic reticulum-resident proteome. Cell Reports, 35(4).
DOI: 10.1016/j.celrep.2021.109040