Nicotine Salts: How do I verify the nicotine concentration?

submitted about 9 years ago by station_nine

I just realized tonight that I didn't test my batch of NN Signature nicotine salt solution. So I weighed in 1ml, added water and Bromothymol Blue and it instantly turned yellow.

Of course this is to be expected. Freebase nicotine is slightly alkaline, whereas the salt formulations are all acidic, and well beyond the blue-->yellow color change.

So... If I want to verify that my 100mg/ml nicotine base is in fact 100mg in each ml, what indicator should I buy, and what should I add to neutralize?

It looks like either Bromothymol Blue or Brilliant Yellow can be used to sneak up to pH 7 from the other side, but to come up with a meaningful result, I'd need to know the starting pH of the nicotine salt, right?

I guess I can also use Resazurin to determine the base pH, then plug that into my calculations once I've titrated it to 7 pH.

Clearly I'm not a chemist. If anyone here knows of a simpler way, I'd love to hear it.

I'm off to buy some sodium hydroxide...

Comments

3 points

by station_nineabout 9 years ago

Ok, so these will work to determine the initial pH. I still need to figure out if there's anything special about pH 7 or if there's a better endpoint for the titration that an indicator will quickly transition at. Also curious if these salt formulations have any buffering properties that I need to be aware of.

3 points

by Reldofabout 9 years ago

you can create a solution of Bromothymol Blue (a few drops in a small bottle will do), 5% acetic acid and the rest distilled water. Thats what the nikitest kit solution is, instruction can be found here https://www.nikitest.com/nicotine-test-kit-instructions/

1 points

by station_nineabout 9 years ago

Thanks, but that won't work as far as I can tell, because the nicotine I'm testing is already acidic. The Bromothymol Blue turns yellow the instant I add it to the nicotine under test, before any other reagent is added.

1 points

by engmiaabout 9 years agoOne of "The Damned"

Hm, don't you just dilute the salt unflavoured and test that with the current methods the ready solution?

edit: Dumb question from my side, you already buy them pre-diluted. Could you explain why the regular methods don't work, I don't get it unfortunately and I'm really interested

2 points

by station_nineabout 9 years ago

The pH of most nicotine bases is around 8. When using a test kit, you add acid in small amounts until the total pH drops to 7. At that point, the indicator changes from blue to yellow to tell you the mix is now neutral. You then do some math with the amount of acid you added to determine the concentration of nicotine.

In the case of these nicotine salts, the pH is closer to 5, which is already acidic. Adding acid won't increase the pH. Some base needs to be used instead.

So I'm wondering what base I should be using as the neutralizing agent, and what the math is to determine the concentration.

1 points

by engmiaabout 9 years agoOne of "The Damned"

Ah that makes sense now, thanks!

1 points

by T_Maceabout 9 years agoTobacconist

Did you try emailing the company? I'm sure they know the ph.

1 points

by station_nineabout 9 years ago

Just did. Quite an obvious first step. Should have done that before posting here.

1 points

by Sandman0about 9 years ago

EMail admin@nudenicotine.com and ask.

Every order I've ever placed with them has included an info sheet with the analysis for that batch in the shipping box.

I would assume you can use any nicotine titration kit to test it, including the one NN sells.

1 points

by station_nineabout 9 years ago

> EMail admin@nudenicotine.com[1] and ask.

>Every order I've ever placed with them has included an info sheet with the analysis for that batch in the shipping box.

I did just that right now. Unfortunately I have this problem (a character defect, really) wherein vape mail is ripped open and all non-product items are tossed aside. I can't find the sheet at the moment, but hopefully NN comes back with some good info.

> I would assume you can use any nicotine titration kit to test it, including the one NN sells.

They won't, since they all use an acid to neutralize the nicotine. In this case, the nicotine is already acidic.

1 points

by bikeatefoucaultabout 9 years ago

Al I can offer is that I just got some nn smooth, and any thing over 1.5mg/ml (I normally order 0mg & 3mg juice and mix down down to 1mg) will typically make me cough and I'm fine vaping this at (what should be) 1.8-2mg/ml (first time making my own juice, I wanted to see if the smooth would let me up my nic level a touch since I was going through so much juice)