Fidelmios
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Any tips on drying Fluorescein?
Hi all
Recently I bought about 20 highlighters and extracted the dyes inside. Using isopropanol I was able to get the dyes into solution quite easily, and
then using heat I drove off most of the solvent, but a little remained. It is because the small amount of solvent that the solution is almost like a
caramel/molasses consistency. I have some Calcium Chloride on hand, but I wonder if that will be enough to pull the excess water away from the dye?
Could I simply put it in a laboratory microwave and drive off the water?
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Boffis
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1) are your sure the dye is fluorescein?
2) is the dye water soluble, fluorescein is fluorescent as the alkali salt which is water soluble?
3) how much fluorescent dye do you think is present in 20 highers?
4) apart from the dye there are probably other fillers and binder present too to give the inks its required flow characteristic eg a glycol like
alcohol.
This has got to be the most difficult and expensive method imaginable of getting fluorescein if indeed it is fluorescein. You can test the dye for
fluorescein by making a spot on filter paper, adding a drop of very dilute sodium carbonate solution (say 1g/L) and then exposing to bromine vapor,
fluorescein will turn bright pink were as most dyes are bleached. This test may not be 100% characteristic but if it fails you are definitely barking
up the wrong tree.
Try going to a plumbing store and buying yellow drain tracing dye. This is usually a mixture of 20-50% sodium fluorescein with the remainder being
sodium carbonate.
As for drying what you already have you need to isolate the dye first which you clearly haven't.
[Edited on 2-3-2017 by Boffis]
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