Introduction: How to Make Fluorescein From Highlighter Markers

The above video demonstrates how to extract the chemical fluorescein from highlighter markers using no other chemical besides common rubbing alcohol. As is demonstrated in the video, fluorescein is spectacular to watch dissolve into water, especially under black light. Below is a list of other excellent videos that feature fluorescein.

Dr. Nozman's demonstrations (subtitled in English):


NurdRage (An excellent tutorial to make Fluorescein in the lab):

In addition to the above videos here are several links describing the process by which Fluorescein is used to detect trace amounts of blood:


amjy88 (author)2013-07-27

Can this be done with other highlighter colors or just yellow ones?

NightHawkInLight (author)amjy882013-07-27

Only yellow ones will have fluorescein, but other colors may also use somewhat interesting dyes.

What are controlled variables in this experiment??

What dyes exactly are contained in other highlighter colors?

How does the red/green fluorescein get used in yellow highlighters?

It changes colors depending on the concentration and the angle that it's looked at in certain lighting. If you have a test tube of the concentrated liquid one side will look yellow, the other red as you hold it up to a light. It's weird stuff.

pg1315 (author)2013-09-24

so since you said the Fluorescein is nontoxic, does that mean i can mix it in a drink to make it glow under a blacklight?

NightHawkInLight (author)pg13152013-09-24

It's non toxic, but from what I've read it does make you nauseous if you ingest it. There also might be some other chemicals in a highlighter that might not be as safe. To make drinks glow, mix them with club soda. It will glow blue under black light.

Do you mean "Tonic Water"?

Or is it the same thing?

could I glow if I drank it?

MadisonH (author)2014-08-27

This is my science project I'm using!

HavocRC (author)2013-12-19

How long will it last? Like if I put it in a bowl of water, will it begin to fade after a few days?

NightHawkInLight (author)HavocRC2013-12-19

It will last several weeks at minimum.

WinterSoldier (author)2013-09-20


mymyjames2000 (author)2013-08-22

Is it possible just to squeeze the inner tube instead of messing with the bottle and alchohol?

gassie202 (author)2013-08-14

Just a tip, if you want to obtain fluorescein powder, you can use the following steps:
1. obtain a flat glass surface, pour the flourescein on it in batches small enough that the surface tensoin keeps it together.
2. Use a hairdryer on highest heat at the lowest speed. watch out that you dont hold the hairdryer to close because je might blow the solution everywhere.
3. keep this up untill the fluorescein dries up and sticks to the glass.
4. use a flat metal, glass or plastic object like a razor or old credit card to scrape all the fluorescein off the glass and collect it in airtight pot.

A glass surface is not a must, but the powder is a lot easier to see. So you wont get fluorescein anywhere you don't want it.

Nice tutorial btw, had no idea markers contained that much of the stuff.

Gravity Boy (author)2013-08-04

Make not "mark"

Gravity Boy (author)2013-08-04

Would this florescence with an AC component around it? Meaning could you mark an electroluminescent wire or plate using capacitance?

Undwe (author)2013-08-04

highlighters have never been more interesting

dmb321 (author)2013-07-30

awesome I will no longer see highlite markers the same way!

Chinasaur (author)2013-07-29

Would be cool if there were a reasonably diy reaction to conjugate this to amino acids for some diybio /in situ/ hybridizations (assuming you can also get oligonucleoties synthesized somewhere...)

BABLOON1424 (author)2013-07-29


Project 23 (author)2013-07-29

Dufva (author)2013-07-28

This is great fun, what percentage is the rubbing alcohol?

And how long did it take to evaporate the alcohol? :-)

NightHawkInLight (author)Dufva2013-07-28

I used 91% alcohol. The higher the concentration the better. It took about 20-30 minutes to evaporate without allowing it to boil very much. Too much of a boil causes little specks to get on everything around the pot.

Gabrock (author)2013-07-28

Awesome. What concentration has the alcohol you used?

billbillt (author)2013-07-28


theknexlord (author)2013-07-28

I like how you showed us how to thk

action pig (author)2013-07-27

Very nicely done! This is now on my to-do list.

Camtron0 (author)2013-07-27


nerfrocketeer (author)2013-07-26


About This Instructable




Bio: I like turning boring things into awesome things! Usually on video.
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