what's the chemical reaction that takes place in a marquis kit?

[lab slave]

Ok, someone may have covered this already but I couldn't get anything useful to come up using the search engine. Nothing seems to come up on google either.

This is for someone who knows a decent bit of chemistry. I know you guys are out there.

So what actually causes the reagent to turn purple/black? Can someone explain what's going on in the form of an equation?

ie C11H15NO2 --- H2SO4 + CH2O

My chemistry is very rusty. My first guess was that the reaction involves the oxygens that you get with the MDMA analogues, which is why it's not easy to tell the difference between MDA, MDEA, etc. Then I noticed that bkMDMA goes bright yellow which is a big flaw in my idea.

Maybe there's no easy answer.

This started when I analysed a bunch of clear crystals, getting a quick purple black reaction consistent with MDMA, however the substance is not MDMA or MDA, neither is it opiates or DXM. Can I therefore presume that this is MDEA or MDBD? Or are there in fact an endless range of active and inactive MD analogues that will test similarly.

Ok thanks, hopefully this post gets some nice nerdy responses.

 

[Bearlove]

I'm not sure about what you have written but here is my understanding on the subject!

The kits are normally sulphuric acid and formaldehyde -

The formaldehyde dehydrates/complexes with the organic compound but needs the presence of sulphuric acid to catalyse the reaction (formaldehyde can either be reduced to methanol, oxidized to formic acid or form ketal like polymers with amine functions of compounds).

I hope this makes sense? If not then check with one of the guys in the advanced chemistry section :D

 

[lab slave]

Thanks - i didn't know there was an advanced chemistry section - i'll check it out!

What you wrote about the reaction is useful as well.

I was thinking about it a bit more already anyway and it seems likely that there are dozens of phenethylamines which will react identical to MDMA. And unfortunately there are more and more phenethylamine RCs out there so the test kits are going to be much easier to fool.

 

[Dmytry]

different colors from the test are caused when the reagent changes the chemical structure of the powder being tested. specifically conjugated bonds cause absorption at different wavelengths. bk-mdma has more conjugation than mdma because the ketone turns into an enol in solution, adding to the conjugated system, and absorbs at a different wavelength

 

[Utahrd]

Thanks so much for posting this. I have had the same questions for a while, definitely a topic worthy of discussion