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encipher
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Fluorescein
Hi,
Does anyone know where is a good source of acquiring Fluorescein. I have checked my usual chemical suppliers, and also looked up the synthesis (which
is too advanced for me). Any ideas on the availability of it here in the United States?
I have however found the following on ebay:
http://cgi.ebay.com/Fluorescein-sodium-Indicator-Reagent-100...
It is Flouroscein sodium salt. My use of flouroscein will be for the visual aspect only (its flourescence). Is that salt also suitable?
Also, if anyone knows another compound with a similar effect, please mention it.
Thanks
[Edited on 1-7-2007 by encipher]
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Sauron
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Fluorscein is easy to make.
You need phthalic anhydride and resorcinol. You need either concentrated H2SO4 (but only a little but) or anhydrous zinc chloride as catalyst. The
procedure is in Vogel's book (Practical Organic Chemistry 3rd.Ed.) which you can download freely from the forum library.
Fluorscein is a FD&C color. (Food, Drug & Cosmetics) I think it is FD&C Yellow but I frget which number it is. I believe it is the sodium
salt you want. It fluoresces in solution even whenvery dilute. They use it to trace the course of underground rivers and streams.
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garage chemist
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Fluorescein itself does not fluorescence, its only the sodium salt that does. So you want the sodium salt.
And the synthesis of fluorescein is not advanced at all. Also the chemicals for it are cheap.
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Sauron
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Quite right. I did it when I was a young teenager, only not very efficiently because I did not comprehend the need for a Lewis acid catalyst to
"condense" the two mols of resorcinol with one mol of phthalic anhydride.
Don't let the odd names throw you either. Resorcinol is just 1,3 dihydroxybenzene (or 3-hydroxyphenol if you prefer).
And phthalic anhydride is 1,2-benzenedicarboxylic anhydride.
They are cheap because they are vast importance industrially and thus, mass produced.
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encipher
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| Quote: | Originally posted by garage chemist
Fluorescein itself does not fluorescence, its only the sodium salt that does. So you want the sodium salt.
And the synthesis of fluorescein is not advanced at all. Also the chemicals for it are cheap. |
Yes, but I do not have any of the chemicals required to synthesize it, so I would end up having to make those etc.. which is why I said it would be
too advanced. Organic isn't exactly my strong point either.
But thanks, I guess I'll be getting the sodium salt then.
Also, would you happen to know of any other flourescent compounds that are low in toxicity?
Thanks again.
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Sauron
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Ever see "Ra-Animator"? Remember the green-yellow glowing, radioactive looking liquid in the syringes? THAT is sodium salt of fluorscein. Just
remember a little goes a LONG way.
Ever have corneal abrasion? Or otherwise have an eye exam requiring the slit lamp? If so remember the orange strip of paper that the doctor or nurse
just touched to your eye? THAT was sodium fluorscein. and that's why there's a UV lamp in that instrunebt,
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Nicodem
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I remember a medicine containing fluoroscein that I used years ago to cure some fish disease in my aquarium. I don't remember what the disease was but
I guess it is only added as a color marker (it makes the aquarium water glow green). So, if you only need a little to color something you might check
an aquarium store.
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matei
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| Quote: | Originally posted by encipher
Also, would you happen to know of any other flourescent compounds that are low in toxicity?
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Rhodamine B has a very nice magenta (or pink in very dilute solutions) fluorescence. However it is rated R: 22-41, which means "Harmful if swallowed"
and "Toxic in contact with skin".
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YT2095
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I believe Quinine is another compound that`s non toxic in small amounts and will fluoresce under UV.
just out of curiosity, is there any way to break fluorescein down into anything useful, I have about 90g of the free acid, More than enough for
several lifetimes of green glowy stuff!
\"In a world full of wonders mankind has managed to invent boredom\" - Death
Twinkies don\'t have a shelf life. They have a half-life! -Caine (a friend of mine)
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Nick F
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Yeah, quinine does. Ever noticed that your gin and tonic glows slightly blue in summer sunshine? Or REALLY blue under UV in a club?
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YT2095
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that`s the one  )
I just realised, if you`re the Encipher I know, then I`ll send you some Fluorescein if you like, it`s the Acid itself, easy enough to convert to the
sodium salt if you wanted to
\"In a world full of wonders mankind has managed to invent boredom\" - Death
Twinkies don\'t have a shelf life. They have a half-life! -Caine (a friend of mine)
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woelen
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YT2095, I found this reaction, making eosin from fluorescein. It might be an interesting experiment for you.
http://www.versuchschemie.de/topic,4881,-Eosin+aus+Fluoresce...
It is in German, but you should be able to grasp the idea behind it.
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YT2095
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Interesting!
I didn`t wish to mess about with Bromine today, so I made Erythrosin instead
it`s the same synth more or less, just use Iodine instead of Bromine.
maybe when I`m feeling a little better, I`ll try the other Halogens too.
\"In a world full of wonders mankind has managed to invent boredom\" - Death
Twinkies don\'t have a shelf life. They have a half-life! -Caine (a friend of mine)
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YT2095
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I just did the Eosin synth, this stuff is Insane!
diluted to 62500:1 and it`s still pink visible, it stains everything it touches with any sort of porous surface incl the sink, and I havent worked out
how to shift it yet, neat bleach doesn`t touch it (NaOCl 5%).
I`ve dyed a wool swatch, and it`s now Acid Pink, so I`m really pleased with it as a dye, I just need to figure a way to destroy it now.
also NaOH doesn`t change the color either, I thought it might alter it.
EDIT: Update, Chlorox Bleach, WILL attack it, it just takes a while *phew*
[Edited on 12-1-2007 by YT2095]
\"In a world full of wonders mankind has managed to invent boredom\" - Death
Twinkies don\'t have a shelf life. They have a half-life! -Caine (a friend of mine)
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anti_vizsla
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re: fluorescein suppliers
Fluorescein is fairly cheap.
Try to get it from Molecular Probes (www.probes.com)
As for using other compounds with similar emission...stick with fluorescein, its fluorescence quantum yield is 0.9.
From my research experience, its the best green emitting organic fluorophore.
N.B. For emission don't use a concentration higher that 10^(-5) M, it will form H-type aggregates which lead to self-quenching.
Carefull, with the pH value used, its also pH sensitive.
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aludel
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I got 10 grams of fluorescein recently, it's a reddish-brown powder, not at all fluorescent. After dissolving a bit in a weak NaOH solution a bright
green glow appears under a blacklight: the sodium salt!
I'm going to try to make fluorescent paint from this (being a painter), the solution itself isn't suitable to paint with. Somehow attach it to an
insoluble carrier to get a pigment rather than a dye...
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py3rhcl3
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| Quote: | Originally posted by aludel
After dissolving a bit in a weak NaOH solution a bright green glow appears under a blacklight: the sodium salt! |
To be exact, the onset of the fluorescence of fluorescein in basic media isn't caused by the formation of the sodium salt, rather than by the
deprotonation of one of the hydroxygroups on the ring. Also the non-fluorescent lacton-form isn't stable in alkaline media.
| Quote: | Originally posted by aludel
I'm going to try to make fluorescent paint from this (being a painter), the solution itself isn't suitable to paint with. Somehow attach it to an
insoluble carrier to get a pigment rather than a dye... |
The problem is that esp. fluorescein is _very_ photolabile and therefore would bleach extremly fast under constant irradiation (daylight). You have to
use a photostable fluorophor when using it as paint....
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joeflsts
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| Quote: | Originally posted by YT2095
I just did the Eosin synth, this stuff is Insane!
diluted to 62500:1 and it`s still pink visible, it stains everything it touches with any sort of porous surface incl the sink, and I havent worked out
how to shift it yet, neat bleach doesn`t touch it (NaOCl 5%).
I`ve dyed a wool swatch, and it`s now Acid Pink, so I`m really pleased with it as a dye, I just need to figure a way to destroy it now.
also NaOH doesn`t change the color either, I thought it might alter it.
EDIT: Update, Chlorox Bleach, WILL attack it, it just takes a while *phew*
[Edited on 12-1-2007 by YT2095] |
YT - In what form did you use Bromine? Did you use it as bromine water or as liquid bromine?
I just complete making fluorescein and I'm now interested in attempting Eosin. I had to laugh at your comments regarding cleanup. While cleaning up
the fluorescein I used 10% Ammonia and damn near gassed myself!
Joe
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YT2095
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I had liquid bromine under a little water, I worked small scale and only had 0.5ml of Br2 under about 2ml of water, but it`s plenty enough to make a
good T spoon of Eosin when dried.
you`ll find that Ammonia added to eosin makes it Really Pink too
Chlorox bleach (NaOCl) will remove inevitable stains that occur but be patient, it`s not instant
\"In a world full of wonders mankind has managed to invent boredom\" - Death
Twinkies don\'t have a shelf life. They have a half-life! -Caine (a friend of mine)
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indigofuzzy
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As for other non-toxic fluorescent compounds, there is Methyl Salicylate (aka oil of wintergreen).
Btw, if you'nz can forgive me for asking: What compound makes semen fluorescent?
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Pyridinium
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if you want an easy source of erythrosin, just use red food coloring. It's mixed with an azo dye though (allura red).
When I'm done w/ stained glassware, caps, droppers, etc, I just leave them in a beaker of bleach for about 4 hrs (though I notice a peculiar trace
odor that's not entirely chlorine- anyone know offhand what that is?)
For clothing and other surfaces I don't know what to use w/o destroying them, though Oxy-Clean might work :-D
Edit: joeflsts, I like your lab write up and pics. Will have to try that experiment when I get the time.
[Edited on 19-3-2007 by Pyridinium]
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joeflsts
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Fluorescein Preparation
Since this topic came up I have been fascinated with the preparation of Fluorescein. I have attached my preparation for anyone interested.
Joe
Attachment: Fluorescein.pdf (316kB)
This file has been downloaded 5286 times
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woelen
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I have done a preparation, which does not require the use of ZnCl2. I did not isolate the fluorescein, but unmistakenly, fluorescein is formed. This
prep is analogous to the prep of phenolphtalein from phenol and phtalic anhydride with conc. H2SO4. This preparation of fluorescein is a nice
experiment on its own. I made a web page about this.
http://woelen.scheikunde.net/science/chem/exps/fluorescence/...
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indigofuzzy
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It's a bit of an odd question, but can anyone recommend an assay for fluorescein? I have some fluorescent yellow-green ink whose composition I have
been curious about. The intent of this is my exploration of copper salts, to see if the Copper(II) salt of flourescein is fluorescent, if it makes
nice crystals, etc.
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YT2095
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well, Fluorescein is just Barely soluble in water, most will just sink or float on the top as a red/brown powder.
the addition of Copper Carbonate will help it dissolve a little better but still only slightly more, and the color of the water soln doesn`t look any
different than if you use NaOH to me.
\"In a world full of wonders mankind has managed to invent boredom\" - Death
Twinkies don\'t have a shelf life. They have a half-life! -Caine (a friend of mine)
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