Effects of Heat on Nicotine Degradation
I want to determine the best bath temperature for speed steeping ejuice via a hot water bath. I want to know the effects of heat on Nicotine concentration, i.e. am I sacrificing potency, and if so how much.
Here is the Test Protocol I am using.
- Make a large batch of 50/50 PG/VG with ~4% nic, no flavoring or other dilutants.
- Fill four 1oz Boston Rounds with this mixture.
- Mark one bottle as the "Control Sample" and set it aside.
- Mark each of the other 3 bottles with 125F, 150F, and 175F.
- Put each bottle in a hot water bath (crock pot) for 8 hours at the specified temp.
- When all batches are complete pull three 5ml samples from each of the four bottles and titrate them, using the average of the 3 titrations as the test result. If any given test result is more than 10% different than the other two, throw it out and redo it as it was probably inaccurate.
To test the nicotine levels I use the following protocol.
Accuracy is affected by sample size, reagent concentration, visual cues of color, visual judgement of syringe level, and technique. I use a larger sample size, and a weaker reagent, for higher accuracy. I estimate my accuracy at +/- 2% or better, hence the reason for testing 3 samples and averaging them, further reducing the margin of error.
- Rinse Erlenmeyer flask, and syringes, with distilled water
- Using a syringe measure exactly 5ml of sample into the flask
- Add ~20ml distilled water (precision not required because water has a neutral ph)
- Add 3 drops of bromothymol blue pH indicator per ml of sample (more if nic levels are expected to be high) and swirl to mix. In this case 15 drops.
- Using a 10ml Class A Burette, dispense a slow stream of 0.1N reagent grade hydrochloric acid into flask (swirling flask continuously) until color starts to change to green.
- Slow stream of 0.1 N HCL down to a drop and continue adding until color changes to yellow, swirling flask after each drop.
- Note how much HCL was consumed
- Multiply HCL consumed by 16.223
- Divide result above by the sample size, in this case 5
Test results are in:
Control Sample: 36.01 mg/l
125F Sample: 35.69 mg/l
150F Sample: 33.09 mg/l
175F Sample: 32.12 mg/l
So it was clear, heat degrades the nicotine. The effect wasnt too bad at 125F, but at 150F there was an 8% loss, and at 175F there was a 10% loss.
This isnt the whole story though, take a look at the conversation I had with a chemist. The layman's version is that the heat can turn nicotine alkaloids into different alkaloids, ones that would still test positive as nicotine in a titration test but might not have the same stimulant effect on the human body.
The Crock Pot heating up, controlled by a Sous-vide controller (accurate to 1/10 of a degree):
The Titration apparatus:
©2017 Mike Petro. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
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