Fluorescein (Glowing rivers)

Edit: Looks like I might be off on this.

If you're in Chicago, the river will be green this weekend. For that, you can thank fluorescein:

i-d081dec9720c079d7024ee24c6a40292-fluorescein.gif

Fluorescein is strongly fluorescent - if it absorbs a photon, 97 times out of 100, it will be re-emitted as light (see yesterday's entry on fluorene for more information).

Fluorescein is a phenomenally useful fluorophore; it finds use in biology to fluorescently tag molecules, as well in medical imaging.

Happy St. Patrick's day!

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