What reaction is going on here?

[Trail]

Hey all..

We've all noticed e-liquids turning darker during steeping. Mostly going towards yellow / amber.

The nicotine degrades and turns darker in color.

But ive noticed something interesting, I've mixed Inawera's Mocca wich is a clear liquid, with 20mg NIC and it turns into a very nice bright pink/red liquid. I didn't think twice about it because its always interesting to see the liquids changing colors while steeping.. BUT..

A friend wanted Mocca without nicotine, and that Mocca bottle stay's totally colorless. Exactly the same PG/VG 50/50 ratio and from the same bottles of PG/VG liquids, the only difference is there being no nicotine.

So I was thinking.. the facts:
The mocca flavoring is totally clear
Nicotine on its own or in plain PG/VG turns yellow -> amber
Nicotine is now a proven factor for discoloration in this experiment.

What is happening? It seems the nicotine is doing a REACTION of some sorts with the Mocca flavoring.. wich then begs the question wouldn't this automatically mean the nicotine is degrading much faster.. and what the heck is created in this supposed reaction.. I know whatever it is it still tastes good lol.. but it could even have become a toxic substance I'm vaping..

Any chemists around? here? lol
~Trail.

 

[jcal]

Interesting ,not a chemist but will follow thread just to see what they say

 

[Hoosier]

Reads like the flavoring is helping to produce cotinine (Oxidized nicotine) to me.

 

[WileECoyote]

Same thing happens to my clove. all ingredients are clear. When I shake, bam, magic.

 

[Kurt]

I am a chemist, but I am not sure what is happening here. I have thought about this for a long time, however, and the pink hue being observed is well known around here.

Here is what I think is happening. Nicotine oxidizes to nicotine-oxide with O2. On its own this is a yellow-brown compound. Color of the compound arises from what wavelength of light is most absorbed by the compound. We then, in general, see what is not absorbed of the remaining wavelengths of visible light...that is, we see the complementary color. What wavelengths of light are absorbed, however, can be affected by the environment, solvent, how the nic-oxide molecules are oriented with each other, and if they are interacting, even weakly, with other molecules. These effects can shift the wavelength of the light absorbed, and thus shift the color of what we see.

It does not take a great deal to shift yellow-orange light to the red range. "Red shifting" is common, and can arise from a molecule that has charged atoms simply interacting with its dipole with another polar molecule. I think vanillin is one such molecule that can shift the color of nic-oxide without actually reacting with it is forming a new compound. Call it a "complex", that is, a weakly interacting pair. By weak I mean there is no chemical bond, just a charge-charge interaction. I do not think it is an overt reaction, and I don't think it is making something toxic...although that says nothing of the safety of the flavor compounds themselves, jury is still out on some of these, but I don't think something new is being added to the juice.

This rose-pink effect seems to be most commonly seen in juices that have vanilla in them, although I have seen it with other flavors too. I am betting the mocha has vanilla in it. And it does not seem to always happen with vanilla, just occasionally, in my experience. I personally have seen it only with vanilla, or flavors containing vanilla, but there are reports from other flavors too. Then again, most flavors we use are a cocktail of a large number of different compounds, and vanillins are pretty popular in the sweet flavor industry.

I do know of one instance where an unflavored VG-nic became pink. Never found out what the cause was, and the nic was replaced without question, but consider this: there are other alkaloids from tobacco in trace quantities in any batch of nicotine free-base. Almost impossible to remove them entirely, and they also oxidize to a colored product, but these may not be yellow-orange, they may be red. Again, I've not done any analysis on this problem, and what I am saying here is largely conjecture, but to a chemist's mind, it seems very plausible. Consider also that the relative amounts of other alkaloids in a batch of nic can vary from source to source. Some tobaccos might produce more mysomine, some more nornicotine, etc.

Down the road, this might be disproved, and there actually is something toxic forming to be concerned about, but I personally do not think it is a problem. Nor do I currently toss juices that go pink. Nic-oxides are not considered toxic in of themselves, and I doubt oxides of other tobacco alkaloids are either, but I don't think that has been studied. My gut says there is no problem here.