Making Fluorescein

TL;DR

Learn how to make fluorescein, a versatile molecule with low toxicity, used in medical diagnostics and highlighter markers.

Transcript

Fluorescien's a pretty interesting molecule with quite a wide variety of uses because it's quite fluorescent but has a very low toxicity. In particular this low toxicity allows it to be used for everyday things as well as in the medical field for diagnostics. I actually find it pretty interesting that the toxicity is low enough that it can be injec... Read More

Key Insights

• 😘 Fluorescein has a wide range of uses due to its low toxicity and fluorescent properties.
• ❓ The synthesis of fluorescein involves a series of chemical reactions and catalysts.
• ❓ Purifying fluorescein can yield a dry powder, while dissolving the crude product provides a quick solution.

Questions & Answers

Q: What are some uses of fluorescein?

Fluorescein has various uses, including medical diagnostics for mapping the vascular system and diagnosing diseases, as well as being a common ingredient in highlighter markers.

Q: How is fluorescein synthesized?

Fluorescein is synthesized by reacting phthalic anhydride with resorcinol using sulfuric acid as a catalyst. This reaction undergoes a series of steps, including Friedel-Crafts reactions and Fischer esterification.

Q: Can you skip the purification steps when making fluorescein?

Yes, if you're looking for a quick solution, you can dissolve the crude product in sodium hydroxide solution without going through the purification steps. However, purifying the fluorescein will yield a dry powder.

Q: Why does fluorescein appear red in a concentrated solution but green in water?

In a concentrated solution, the high concentration of fluorescein molecules quenches their own fluorescence, resulting in red color. When dropped into water, the concentration decreases, allowing fluorescence to appear as green.

Summary & Key Takeaways

• Fluorescein is a low-toxicity molecule used in medical diagnostics and highlighter markers.

• The synthesis of fluorescein involves a chemical reaction between phthalic anhydride and resorcinol, catalyzed by sulfuric acid.

• To isolate fluorescein, the crude product is dissolved in acetone, followed by multiple extractions using diethyl ether and water.