Sciencemadness Discussion Board

Extraction of highlighter dye V2

Fidelmios - 18-6-2017 at 21:14

Hey all,

I am back with another set of experiments I am starting to run, this time the extraction of more dye from highlighter markers. I know its not cost efficient, but it is just to add to the collection I have going. Of very pretty, and historically relevant dyes. So I ordered a 12 pack of these really cheap markers from China from Ebay and I am having a bit of trouble pinning down the dye used inside of them. I figured that it would be a similar dye to those found in Walmart markers, because they're probably the same ones just recased.


Okay, simple enough to find the SDS on Walmart a handy search place for them, except that OSHA apparently doesn't require an msds to be provided on markers. (I know it sounds like bullshit but all the SDS for Sharpie read the same). So I figured offbrands might work too, expect they list their dye as "ink", or "Trade secrets" I was able to find a 3 pack where the only chemical sounding unfamiliar is 5-Chloro-2-methyl-3-isothiazolone which I assume is the binding agent keeping the ink from running once its on the page.



I figured I would just brute force the search by googling "What the fuck is in pink highlighters" and came across this. Which, while informative, isn't correct (to my knowledge). It states that pink markers are made using Rhodamine B, which is a carcinogen right? So they certainly can't sell those markers in places like California. So I am at a loss. If anyone has an idea of where I can go from here, or perhaps correct anything I've stated wrong, please let me know!

unionised - 19-6-2017 at 11:01

Could be
https://en.wikipedia.org/wiki/Eosin
based on the colour.

UC235 - 19-6-2017 at 16:37

5-chloro-2-methyl-4-isothiazolin-3-one is a biocide to keep mold and bacteria from growing on the product.

A few thoughts:

See if it's pH sensitive in solution. If there's a color change, what pH it occurs at could help you identify the dye.

Do some quick paper towel chromatography to see if it's a single dye or a mixture.

Fidelmios - 19-6-2017 at 22:50

Quote: Originally posted by UC235  
5-chloro-2-methyl-4-isothiazolin-3-one is a biocide to keep mold and bacteria from growing on the product.

A few thoughts:

See if it's pH sensitive in solution. If there's a color change, what pH it occurs at could help you identify the dye.

Do some quick paper towel chromatography to see if it's a single dye or a mixture.



I think I have some hardware grade HCL, and citric acid. I also have some sulfuric acid but idea rather not resort to using it yet. Should I be able to test this using HCl? As some one stated above it may be Eosin, regardless I could start by concentrating the solution down by removing the biding agent by running 90% isopropanol through the dye packs.

feacetech - 20-6-2017 at 17:23

Quote: Originally posted by UC235  
5-chloro-2-methyl-4-isothiazolin-3-one is a biocide to keep mold and bacteria from growing on the product.


Isothiazolinone's nasty things, i spilt some on my shoes (industrial stength) a number of years ago.

I eneded up with large blisters and a rash on my foot.

after that (a month or two) i developed Psoriasis (which i had never had before) which finally went away after about 3 years.

Fidelmios - 21-6-2017 at 19:41

So update: I used 91%isopropanol to wash the dye tunes clean of most of the unknown dye. This dye appears to posses a similar quality to that of fluorescene where the color is dependant on the concentration. When light is passing through it the solution is a vibrant pink, when not it is a light tea pink color.

Atop this, there appears to be an insoluble bit of powder clumping around the solution. It appears white when dried and watshed. I am currently trying to filter it off, as the coffee filters are not doing so well. I thought this substance to be a water soluble binder but it is not soluble in water, or propanol.


While removing the dye I got quite a bit on my hand, and the white powDer dried on a fingernail. After washing with a bit of acetone based nail polish remover, the stuff came right off
I'll update you guys if I lose a finger, but I think I'll be fine
IDE love to figure out what that stuff is.

DraconicAcid - 22-6-2017 at 14:21

http://www.compoundchem.com/wp-content/uploads/2015/01/The-C...