Any interest in determining nicotine--by DVAP

[DVap]

On the vape volume, it's pretty easy to take a plastic bag of known internal maximum volume, inflate it, seal it around the outside of an e-cig such that the atty holes are inside the bag, and time the vaping required to empty the bag.

For a 510, with all holes open, I did this with a 750 mL bag, time was 60 seconds for 12.5 mL/sec or 60 mL for a 5 second vape. By taping one or more of the atty holes, the resistance can be increased, and the vape volume lowered correspondingly.

I'll probably do the test with an auto-battery 4801, which has a lot of resistance with only 2 holes (and I can tape one of them if needed to tweak the flow resistance). I've got the extended volume carts for the 4801 (0.5 mL) which hold the same volume as a 510 cart. I'd prefer to use an auto-battery 401 (quite superior to a 4801, IMO), but the 0.3 mL cart volume of the 401 is too limited for what I want. I could use multiple carts, but the integrity of the weighing is very important, and the less I futz with the e-cig between initial and final weighing, the better.

The trick now is to take the suggestions on surfaces and find a HDPE bottle that's strong enough to stand a vacuum to which I can attach a valve and have the seal be vacuum tight. Being able to see through the vacuum container does seem awfully attractive.

[exogenesis]

OK, 60ml it is then ,
so as you say 60ml air/puff & 0.006ml juice/puff = 100 puffs for 6 litres & 0.6ml, QED.

Although isn't it bound to slow down as the vaccuum reduces, wonder what the pressure diff.
has to drop to before battery stops being activated ?

Having second thoughts about advisability of using plastic,
reason is similar to what you said about PTFE being used to adsorb nicotine (from air).

The good 'ole Ruyan report:
http://www.ecigarettedirect.co.uk/ex...y-report.pdf#8

goes on about different puff sizes (38 & 60 ml) and :

In the first experiment, nicotine was not detected after the 38 ml puff. Nicotine is known to
adhere to surfaces, and it may have adhered to the side of the Tedlar bag.

Or maybe strong surface adsorption is specific to F containing polymers (like PTFE & Tedlar)
and HDPE would be OK.
Then again any large surface area might take up a substantial proportion of the nic. ?

Not wanting to be a nay-sayer, just exploring the pitfalls, that one might be a bit of a bgr.

[Doctor Vapor]

I haven't gone through every post in this thread, but here is an easy test to determine nicotine levels in DYI.

check out this post, now a convenient sticky.

http://www.e-cigarette-forum.com/for...-nicotine.html

[exogenesis]

Gotta say that method is based on DVap's method given in this thread,

e.g. these posts:

post #26
Original full test method

post #28
Simplified test method

post #39
A potential nicotine test kit


but I guess it helps to have it modified for the (possibly) more easily purchasable acid
(0.12M sulphuric rather than a 0.10M hydrochloric standard),

edit: at least some of the above links are also in the modified-method post,
& I assume Þornbjörg asked DVap for permission to repost his work ?

[DVap]

Gotta say that method is based on DVap's method given in this thread,

this post:
http://www.e-cigarette-forum.com/for...tml#post550005

but I guess it helps to have it modified for the (possibly) more easily purchasable acid (0.12M sulphuric rather than a 0.10M hydrochloric standard),

edit: good to see the above link is also in the modified-method post .

I think you linked the wrong post, exo.

I was glad surprised to find that my method has been reposted with modification to make sourcing the acid easier (though a web search will turn up plenty of 0.1 N acid for sale). I was perhaps a bit nonplussed that this adaptation had been sticky'ed, since honestly, I would have considered that my prerogative having done the heavy-lifting. But seeing as I am lazy about such things, my overall reaction was to shrug it. It's a useful thing to have sticky'ed, and Þornbjörg's attribution to the source is adequate (though I did ask him to add the references after the fact). It was, perhaps, a bit comical to have somebody post in here to let us know someone had figured out a nicotine determination.

Was his thread really necessary? Probably not. Is it useful? I suppose so. Could it have been done more gracefully? Probably. Do I feel inclined to monitor it to answer tough questions? No, he's on his own. Am I going to lose sleep over it? No.

[Vaporer]

CNubel,

You might want to check out post #'s 365, 374, 377, 386 & 408 of this thread.
This DIY'er sticky should be referred to more of a tacky. I see where the ref to this thread an DVap was made. Looks like a convienient edit addon for a CYA.

Comments in this thread from the poster "Since I'm entrepreneurial myself, and planning on going into eliquid manufacture", "I looked at your numbers and I'm not quite getting how to figure it, so any chance you could give me the approximate values for your 1mL test system using .12N Sulfuric Acid? ", ", I'm not the proud owner of a chem degree", "There are few here qualified to do what you are doing, and even less with the capability of doing it. " .
Just a few excerpts from the posts.

Wow.......as usual people willl blindly praise and follow. I'd love to be there when all the people that are leary about what nic content is from 2 diff strengths mixed does all this and slams vendors with shoddy results.

This is better suited left to the REAL chemists ( I am not one), or at least kept in the confines of the originators thread so they can try to correct errors, assumptions and such from an educated standpoint.

I'll now return the thread back to real science.

[exogenesis]

Update the links in my post above , are they the right ones ?

Well said Vaporer, I think that needed to be stated,
I think Dvap is too objective to say anything more than he just did

[exogenesis]

From another thread:

The only problem I see with this method is that many e-liquids contain acid(s). As such, the test will not provide extremely accurate results. For example, all four recipes at the wikipedia article list a concentration of acid from 1 - 2.5%.

DVap has recognised this as a potential problem:
This has been mentioned/discussed in this main thread in these posts :
http://www.e-cigarette-forum.com/for...tml#post553361
http://www.e-cigarette-forum.com/for...tml#post562971
http://www.e-cigarette-forum.com/for...tml#post565353
http://www.e-cigarette-forum.com/for...tml#post614380
http://www.e-cigarette-forum.com/for...tml#post617006
http://www.e-cigarette-forum.com/for...tml#post618680

Potentially a way to recognise ia a juice has acid additives is by using a titation curve,
which changes starting point & shape, still to be proven though:
http://www.e-cigarette-forum.com/for...tml#post620704

JC juice is known to have citric & acetic acid added (<1% each, but how much?),
http://www.e-cigarette-forum.com/for...tml#post649918
other than that I don't think the Wikipedia recipes are necessarily representative
of many other juices (?), certainly not of the newer pure juices
('pharma' or getting close to it) that are becoming more prevalent.

Would be interested to know what they mean by 'organic acid', citric & acetic are organic acids afaik.

[Vaporer]

Also, it should be noted that the testing done here has been on minimum contents liquid as a whole. ie....flavorless.....nicotine and PG as a basis for determination.

The "extra acid" was only an added observation of being included on some labeling and was more discussed as an adsorbtion interference possibility initially due to a pH shift. It was then being approached as a posibility for error as this thread progressed.

Edit: I really have a problem with using Wiki as a valid source. I guess it's due to that little "edit" that ANYONE can click. Sure, it logs your IP as the editor, but it doesn't stop anyone from posting incorrect information that may be seen for a long time before being corrected. An IP can be "ghosted", but that's beyond the scope of this thread and another lesson better well not taught.

[kinabaloo]

Moreover, additives of any active kind (such as an acid rather than say as ester) might affect the nicotine loss and thereby or otherwise, especially if non-vapable, positively lead to deposit build up and potentially toxic decomposition products.

btw, really looking forward to DVap's experimental findings, particularly the nitrogen test. Whatever becomes of the nicotine could be a cause of more toxins than tobacco residues or dry residue decomposition. Knowing to what extent the loss is due to oxidation (the leading candidate) is a key first step. Either way, some kind of chain-reaction might be involved given the scale of the loss (as can occur with some free radicals in certain circumstances).

ps: given the low flash point, although seemingly unlikely i wonder if the nic vapor is actually combusting rather than just fast oxidising once in the gas phase?

pps: the percentage loss at around 50% is intriguing in it's own right - why not just a small part or nearly all of it? Why half is affected differently to the other half? Might be just a boring coinicidence resulting from timescale for example; but curious nonetheless.