Making Fluorescein

Today we will be making some fluorescein! I bought the resorcinol off ebay, and I used the phthalic anhydride that I made in a previous video.

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[elshroomness]

"i want to make it because i want to play it." the chief reason why anybody does science things.

[ericcurrier]

Anyone else not sure about the chemistry but really enjoys most of his videos?
The newer videos are incredibly well made but I'm still able to watch his old stuff without feeling like its lacking.

[gavinpalmer]

1:48 Funny, that “stir bar” kind of looks like a paper clip...

[krystianmazgajewski]

I use this stuff all the time with lidocaine to numb eyes!!!!
Makes it possible to view the cornea through the slit lamp on an eye exam with an indigo light that illustrates just like the beakers at the end of the video anywhere fluorescein has accumulated on any abrasions. The eye acts as the water in the beaker and the fluorescence remains unquenched illuminating the areas of higher fluorescein concentration as bright neon yellow/green. Exactly what it looks like at 12:29. You tha bomb.
Thanks for posting!!!!

[supersmashsam]

Cool, if you got some bromine, you could make eosin, the brominated version of fluorescein. I don't have a protocol, but I'm sure you could find one easily.

I remember in my first undergrad lab, we use to perform a simple test to assess for the presence of bromide in a solution. By adding an oxidizing agent to the solution, you convert the bromide to bromine. You then heat that solution under a filter paper on which you've added a drop of fluorescein. If the spot went from yellow to pink, you had bromide in your solution!

[stonent]

Pthalic anhydride just wants to give you a hug.

[ebrombaugh]

Great video - particularly interesting to me because I have an eye condition and I've had many fluorescein angiograms done so the ophthalmologist can detect blood flow in the retina. Fun part about that is the stuff is unchanged by the body and flushes out in urine. I leave the rest to your imagination...

[wgm]

Nile red, i really like your videos. I loved the inclusion of the overall reaction along with the description of the mechanism, please do this in more of your videos. thanks

[writamsinharoychoudhuri]

To separate pure Fluorescein, you can directly add some water ( sufficient amount to dissolve) into the crude product in the rb and boil the mixture at around boiling temp ( using a reflux, of course ), then all the other compounds present will be dissolved in the water ( like, pthalic acid and sulfuric acid or unreacted resorcinol etc ) but Fluorescein being insoluble will be precipitated on the side inner walls of the rb. Then you can vaccum filtrate the product by washing with water. we did this procedure and got nice 86% yield with absorption spectra peak at 488.5 nm.

[Jambivids]

This stuff is great. I've used it as an indicator once

[michrain]

Funny for someone who never had a chemistry set like myself to binge on this channel lol
I need one of those stirrers for my coffee :D

[MrPacMan]

Absolutely incredible presentation. Very concise! Please don't change your format.

[Omnicurious]

What camera do you use? Your footage always looks very crisp.

[aannurag]

Flourescine dye is a very common tool in an ophthalmologists office used almost every hour if not more frequently. It brilliantly delineates any abrasions/ulcers. It's also used for measuring intraocular pressure (applanation tonometry). Very cool!

[Onerock]

you are awesome, keep on bringing it dude. 2 questions ;  how long will the beaker glow if left alone, and how did you clean your equipment up?  looks like it stained all the glass.

[MeatskinWagon]

I learned more info in just 3 videos than I did in chemistry class.

[mikethompson]

The thumbnail for this looks like it could be an album cover

[runcycleskixc]

If you point a decent power 450 nm blue laser pointer (like 200mW) a dense soln of F will glow super-bright (much brighter than one can get with the UV) -- almost like sunlight.

[Ur_local_peanut]

I love how he's just like: "oh well." 1:15 😂 i love it, and even though i dont really understand whats going on, i really enjoy watching his videos 😙

[runcycleskixc]

fluorescein and rhodamine are the two cheapest fluorescent dyes one can buy. They are like 10 quid for 100 grams on amazon, sold as tracers for leaks in plumbing.