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Analysis of electronic cigarette vapor

Discussion in 'Technical Research' started by rolygate, Jan 1, 2011.

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  1. rolygate

    rolygate Forum Manager Admin Verified Member ECF Veteran

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    Sep 24, 2009
    ECF Towers
    Attached below are four PDFs of research on electronic cigarette liquid/vapor that I came across. There are some interesting results, but on the whole the tests were not properly managed, and the results are not coherently presented or in a logical - or usable - format. There are still too many questions to be asked.

    I wanted to examine this research because there is an ongoing issue with Suppliers publishing various statements about the content of e-cig vapor, apparently without there being any evidence to support these statements, such as, "It's only water vapor", and so on.

    Some relevant points follow.

    The vapor was analysed before inhalation / filtration, ie as directly output by the e-cigarette.

    Some of the test set-ups were photographed, and these arrangements all show the e-cigarette being operated incorrectly, in a manner in which it cannot function correctly or possibly at all (inverted). It may be assumed that those experiments where photos were not provided also featured incorrect operation of the e-cig, since the physical requirements of ease of equipment set-up seemed to have overruled the possibility that an e-cig might not work in such an unusual position: upside down, with the battery end high and liquid reservoir/mouthpiece at the bottom.

    An e-cigarette is similar to an electric kettle in operation: a heating element that operates while submerged in a liquid bath. The element must be immersed or a fault condition will exist. In essence, both an electric kettle and an e-cigarette are gravity-fed immersed-element liquid heaters, and operating an e-cigarette while inverted will be the same as operating a kettle while inverted.

    Because the liquid reservoir is in the mouthpiece, and the liquid must run downward into the atomizer, a standard e-cigarette must be operated with the battery/tip either level with, or preferably below, the mouthpiece, or the atomizer will run dry. The result of inverted operation as shown will be poor vapor production, leading to zero vapor production and smoke generation from combustion of internal materials, mainly plastics of different types. The atomizer will run too hot as it starts to run dry, causing it to burn off materials from inside the housing, which might consist of burnt cartridge filler, adhesives or coatings of some kind. It is well-known that melted plastic can result from this, as the cartridge body overheats.

    If operated in this unusual, inverted fashion by a human operator, use would cease immediately after the first puff or two because the taste and heat would make it impossible to continue, as the 'smoke' resulting would be difficult to inhale and certainly unpleasant. In fact it might well be smoke - instead of the correct water/PG-based mist.

    Analysis was not presented as a coherent, full, final percentage result of vapor ingredients, in any of these tests. The most complete analysis showed around 17% as missing percentages not accounted for. This is not acceptable for any kind of usable result, as a full and final analysis needs to show the precise identity of at least 99.5% of the ingredients of the vapor, including of course water if this is present. Omitting the water content even if this is as low as for example 15% will skew the percentages of other ingredients. If the water percentage is fairly high but omitted, the resulting percentages of other materials will be meaningless.

    The most complete result showed, approximately:
    66% water
    13% alcohol
    3% PG
    1.4% nicotine
    ...and around 17% not accounted for.

    It would seem that this particular cartridge contained a PG/alcohol-based liquid [a], which is unusual and cannot be considered representative of e-liquids generally, which often have a 80-20 PG-VG base, and perhaps 2% alcohol in some cases though most have zero. Some e-liquids are 100% VG-based, in practice meaning the base is about 80 - 99% VG and 5 - 20% distilled water, plus ethyl maltol in some cases. High levels of ethanol are not just atypical but anomalous, and some investigation would be needed before it could be accepted that such a result does not indicate intra-laboratory contamination of the sample.

    a. Unless the 'alcohol' measured resulted from melting of plastics or adhesives within the e-cig body due to the demonstrated incorrect operation.
    b. Ethanol or methanol may be added to e-liquid samples to facilitate analysis. This appears to be a standard method when analysing the liquid content of cartomizers: the refill liquid is flushed out of the container using an alcohol, and then analysed. Perhaps there may have been some form of lab contamination here: introduction of materials before analysis that should have been omitted from the result.

    Trying to get some sort of meaningful result from these studies is difficult, but on the evidence presented here it seems likely the average vapor content would be two-thirds water (66%), a small amount of PG (3%), a very small amount of VG (around 1 to 2%), a very small amount of nicotine (around 1%), and a significant amount, about 15% or more, of flavorings (the last being my assumption based on the compounds seen in other analyses).

    This applies to the mainstream vapor, i.e. before it enters the lungs, and not after being exhaled. It is likely that the particulate matter would be lower in the exhaled vapor, and the water content higher. This is because some materials would be absorbed by the body, and also because water vapor is present (added to) in all exhaled air, meaning that even if some water was absorbed on inhale, it would be added to the exhaled air, plus additional carbon dioxide.

    It must be stressed this is simply a guess. The results of experiments carried out and presented like this may well be wrong.

    Real research needs to be done, where the researchers have an advisor present to ensure that (a) the e-cigarette is operated properly, (b) the atomizer is flushed and pre-run before the experiment starts (this has to be done, to avoid polluted primer or burnt-off production adhesives being present in the vapor, as will normally be the case with new atomizers), and so on.

    6. Smoking machines
    Some labs have a smoking machine used for testing tobacco cigarette smoke. These cannot be used for testing e-cigarette vapor as there are multiple issues; an important reason is that the machine can easily be cleaned after tobacco smoke tests, by flushing with clean air - 'air blast' (and there are set protocols for this).

    That method does not work with a water-based vapor as the material clings to the machine's internals and cannot be removed by air throughput - the machine must be flushed in a different way, and so far an efficient and non-damaging method has not been published as a suggested protocol. The first sample tested will contaminate all further samples (as has been demonstrated). This seems to indicate that ad hoc flask systems, perhaps using a large syringe as the vacuum, might be used (for example). We await some sort of agreement on a testing system, usage protocols, and a cleaning protocol.



    PG = propylene glycol = propane-1,2 diol
    VG = [vegetable] glycerine = propane-1,2,3 triol

    You can safely ignore the content of MSDS sheets as regards toxicity unless they quote a very small figure for the toxic amount (ex: LD50 = 60mg). The other info is simply in there for legal purposes and is essentially meaningless, despite the alarmist content. A person would need to drown in the material for it to be harmful in the case of the vast majority of materials for which the MSDS sheet starts out sounding as if it can be used in chemical warfare.

    Take propane-1,2,3 triol for example, the MSDS sheet makes it sound as if it is some sort of deadly poison. But you're talking about VG, which has pharmaceutical licenses for inhalation, ingestion and topical application, and is a food and skincare product. You can inhale it, drink it, bathe in it, do whatever with it. It's a harmless everyday product consumed in large quantities by people everywhere, and broken down by the body into carbohydrates. The only thing you wouldn't want to do with it is burn it at high temperature and inhale the result (acrolein), but despite this being the only practical way it can be harmful, this isn't addressed by the MSDS sheet.

    Exactly the same goes for propane-1,2 diol, or PG as we know it, you can even inject yourself with significant quantities of it without harm since it is effectively inert (as is done - it's used as the liquid carrier for injectable drugs that don't mix with water). The main difference between PG and glycerine, in this area, is that PG has 70 years' history of safe use and clinical research. PG is used in asthma inhalers, and in the nebulizers used by lung transplant patients. (Contrast this latter use with the MSDS general tone.)

    Note that both these materials are approved and licensed by the FDA for inhalation, ingestion and application to the skin, and, in the case of PG, for injection. They are approved to GRAS level, aka Acceptably Safe, and generally regarded as harmless. You will note that this conflicts with the MSDS, which are to be ignored.

    It appears that the main purpose of an MSDS is for transport contractors and bulk chemical storage operators. If staff come into contact with it or there is a fire on the premises, the MSDS can be given to the services responding. As far as the use of an MSDS for everyday purposes is concerned, they have no relevance unless the toxic quantity given is very small. As an example the MSDS for water would include this statement:

    IRRITANT TO THE EYES AND LUNGS. In case of contact, the treatment advised is extended dehydration.

    ...and so on. This is the legally-required content - everything is toxic, in an MSDS. Even pure air would require an MSDS if transported or stored. The contents of the MSDS would make it appear a dangerous material to the untutored eye.


    4 x PDFs
    [PDF 16-3 had to be edited as the 6MB filesize upload failed. All gfx were removed, leaving the text only. It was edited down from 167pp to 15pp. The gfx edited out were GC-MS readouts and not relevant for this purpose]

    Attached Files:

    • 14.pdf
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    • 15.pdf
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    • 4.pdf
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    • 16-3.pdf
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    DaveP likes this.
  2. Seanl

    Seanl Senior Member

    So in a nutshell a flawed test.

    Would have been nice if they did some research before doing this research.
  3. rolygate

    rolygate Forum Manager Admin Verified Member ECF Veteran

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    Sep 24, 2009
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    You have identified the basic problem: researchers think they know enough to enable them to investigate the various areas of interest. In reality their ignorance can make it virtually impossible to produce any meaningful results. This is the single fact that emerges clearly from the majority of trials, of whatever type.

    We know of several where the researchers had to go back and start over, as they became aware of how ridiculous they looked when the results were shown to be fallacious. Any research, whether technical or clinical, needs experienced e-cigarette users as advisors, or the end results may be useless.

    The catalog of errors is usually headed by the use of first generation models as the basis for clinical trials when we are currently on third generation equipment; and testing the vapor by operating the equipment inverted, in which mode they don't work and which introduces fumes from melted plastic into the vapor.

    Even the least experienced vaper would be able to tell them that gas station PVs either don't work at all for the purpose they are sold for, or at least don't work well and are hardly an optimum basis for clinical trials; and that the fumes and smoke from an e-cigarette used incorrectly upside down for ten minutes will choke you. In fact your 12 year old child will probably be able to tell you that a kettle doesn't work upside down.

    This is the level of incompetence we are faced with, when looking at research carried out by both laboratory researchers and clinical researchers. It does little to give you confidence in the results of other clinical research when e-cigarette research is obviously so comprehensively mismanaged.
  4. Seanl

    Seanl Senior Member

    Yep, I went and read some of the other tests as well yesterday (as well as the new method they are using) and even find this flawed.

    I personally hardly ever hold my pv horizontally and if you watch youtube videos of people testing new equipment, showing cleaning processes etc you never see anyone hold a pv horizontally. It's almost always at an angle ranging from 20 to 45' downward.
    I also personally vape with the button pointed upward only about half the time (turning my ego 180' every now and then for the next vape).

    These guys don't even need to speak to people about the subject. just go to youtube for numerous samples of people using pv's

    at least it seems they are slowly realising they have made some mistakes in the original tests and I believe they may just realise subsequent tests are also flawed as they do not emulate human behaviour or normal usage of a pv.

    I also think the darker juices (coffee etc) should be retested with the pv at the correct angle as they would block and heat up a pv much faster than the clear juices, possibly even more so when holding the device vertically or horizontally.

    Nice to see that even these beat a cigarette hands down for this test :)
  5. Eddie.Willers

    Eddie.Willers ECF Wiki SysOp Verified Member ECF Veteran

    Supporting member
    Apr 3, 2011
    Prairie Canada
    Well found, Roly.
    At least these studies form a basis for what not to do in future research.
  6. Ande

    Ande Super Member ECF Veteran

    Mar 27, 2011
    It's like a monkey reading a book upside down.

    Don't tell US what to do, we're scientists. We have to do research to tell the poor misguided USERS what's wrong with what they're doing.

    Really. It's depressing.

    DaveP likes this.
  7. AZCraig

    AZCraig Registered Supplier ECF Veteran

    Dec 24, 2011
    Mesa, AZ
    Wait... so you are saying the VG e-liquids we are vaping (burn it at a high temperature and inhale the result) are harmful because VG turns into acrolein ?

  8. rolygate

    rolygate Forum Manager Admin Verified Member ECF Veteran

    Supporting member
    Sep 24, 2009
    ECF Towers
    Well... not really. Yes, if you can find a way to heat glycerine to the point where it is converted into acrolein. But this doesn't happen in an e-cig, for various reasons. I discussed why, in a post somewhere, but I don't have the link.

    Basically, it's because an e-cig runs below this temperature. In order to exceed the critical temperature - being a liquid-cooled heater - the liquid needs to be exhausted. But, if the liquid has been used up, it can't be converted into acrolein. Tests for acrolein in the vapor show this to be true.

    An e-cigarette is like an electric kettle, in that it is a liquid-cooled immersed element gravity-fed liquid heater. If you turn a kettle upside down, it will overheat because the liquid cooling no longer operates. (The kettle then overheats, and either trips out or melts the interior of the kettle.) But no steam is produced because there is no longer any water present. This is a simplified explanation of why heating glycerine in an e-cig does not create acrolein.

    An e-cigarette operated incorrectly - either inverted, or past the point of exhaustion of the liquid - will produce choking fumes that no human can inhale. However, lab equipment that is analysing vapor cannot detect this point, as all fumes are good fumes, in the equipment's view, so to speak. So these lab tests, as shown, will produce toxic vapor that a human would recognise as unacceptable, but lab tests will not detect as anomalous. This is why some tests show things like phenols (melted plastic) in the results.

    An e-cig must be tested in the lab at a constant 45-degree downward angle, for a maximum of 40 puffs, with a 20- or 30-second delay between puffs to allow correct liquid feeding and avoid atomiser overheating [a]. Other operational conditions may produce anomalous results that the technicians involved will not recognise as a fault condition. Any human user certainly would.

    [a] This is an average protocol and applies to most, but not all, equipment: some types of heads require occasional tipping in order to wick efficiently; otherwise, a 45-second inter-puff interval needs to be allowed. Ideally such heads should not be used in lab tests as there is too great a risk of a fault condition.
  9. egodzilla

    egodzilla Senior Member ECF Veteran

    Jan 12, 2012
    Is it so hard to just test VG fumes for that Acrolein?

    The temperatures used to produce it are really not high, but I think it might be in a high pressure environment ... In any case I would love to see some scientific evidence on it's absence in the vapor ...
  10. throatkick

    throatkick Unregistered Supplier ECF Veteran

    Dec 20, 2010
    I continue to be amazed at the difficulty of properly analyzing vapor and the ambiguity surrounding it. Something's amiss with this.
  11. egodzilla

    egodzilla Senior Member ECF Veteran

    Jan 12, 2012
    I must agree with you throat ...

    I can hardly believe it's something contemporary science can't do before lunch break ... And I am sure some Chinese mass producers have the bunch to fund it. But well, seems no one wants to spend real money on it before they are forced to ...
  12. rolygate

    rolygate Forum Manager Admin Verified Member ECF Veteran

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    Sep 24, 2009
    ECF Towers
    Firstly, the funding is not there. We already know from botched attempts that the minimum cost of a well-run, simple, basic trial of e-cigarette vapor is $150k.

    Secondly, for certain reasons this type of trial requires an expert lab researcher to manage it. It is obvious that journeyman researchers are simply not capable of successfully completing a trial of e-cigarette vapor. This is shown by the number of trials where the results show obvious mismanagement, or the results were incomplete, or where it was demonstrated that the researchers could not comprehend that the operation of an electronic cigarette is fundamentally different from that of a tobacco cigarette. In fact it seems that all trials up to now have failed in at least one major area.

    The mistakes shown are legion:
    - Lists of 'results' where 15% or more of the ingredients of the vapor are not identified;
    - Multiple trials with photos of the equipment being operated upside-down;
    - A trial where they tried to use a cigarette testing protocol which used the same equipment for a series of trials, then found that the second result and all subsequent results were useless as they were contaminated by the first sample;
    - The inability to recognise that water vapor is not smoke, and the multiple ways this impacts testing;
    - The fundamental error of not appreciating they need an e-cigarette technical expert to advise them.

    The most obvious sign of incompetence is that all lab trials so far have been managed by people who think they know enough about the equipment to test it in the first place, a misapprehension that has so far rendered every test useless. It's hard to get this message across, but perhaps one way is to ask if you think a car industry researcher from Lada is going to be able to test a McClaren F1 racecar successfully, at the Lada facility. Probably not - they may both have four wheels but that's where the similarity ends. One does 60mph with a following wind, the other does 260mph. One needs a tractor mechanic, the other needs aeronautical engineers. You could describe both of them as cars - perhaps.
  13. egodzilla

    egodzilla Senior Member ECF Veteran

    Jan 12, 2012
    This are all very plausible explanations. Still I think 150k is not that big of a sum. There are some big companies around like intellicig which is spending 2 million to get their device "registered". I can hardly believe they could not carry out a analysis of the vapor. After all they are selling the product it self so they could supervise the tests ...

    Also, since we know what substances we are dealing with, we do not need to speculate what could appear. My humble logic tinking tells me, organic chemistry is telling us what we need to look for in the carrier substance. Ok, flavors are a different story, but FlavorArt seems to be trying their best on that filed. Also, I think no one is really concerned about the flavor that much since it represents only a small portion of the vapor. Am I mistaken?

    Anyway, you guys are much more experienced in those question. I am just a new user who feels that getting some reassuring clear info is really not as easy as I wished it was ...

  14. rolygate

    rolygate Forum Manager Admin Verified Member ECF Veteran

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    Sep 24, 2009
    ECF Towers
    As with anything you need to follow the money. Who benefits?

    For example Intellicig do this kind of testing but they do not publish it - why should they? They will have a medical license soon. Such a license requires all this kind of testing. They will only test their own liquid in any case. Why test someone else's? Why publish tests to help other vendors? It is not realistic to expect them to do this, in their situation.

    In any case there are firms ten times their size, who could easily afford it. But why spend the money if they don't have to? Why do work that may be used by a competitor?

    These are the motivating factors for vendors. Unless they are forced to do something, they see no need to do it. Also there is the very useful factor that many people want the cheapest possible liquid and don't seem to give a rat's a. what is in it. When the buyers are that naive it doesn't matter what you sell, and until consumers demand provable quality, vendors can sell anything they make.

    FlavorArt are doing what they can. There was no need for them to identify which of their flavors are best or worst for vaping, or to perform lab tests on the result - so full marks to them. No doubt they see it as a marketing advantage to show buyers that they are trying to establish the best quality and the best deal for vapers in the flavorings market. I sincerely hope it works out for them as they deserve it.

    There is good reason to buy flavors carefully as they are the only unknown part of the equation as far as lung safety goes. It is extremely unlikely that e-cigarettes can cause any kind of cancer, heart disease, vascular disease or other issues caused by smoking since there is no smoke, carbon monoxide, tar or anything else in the liquid refills that can cause any of these health issues. However there certainly is potential for lung issues of one kind or another, so that is where we should look to see if safe practices are being followed.

    It is very hard to tell what is in the vapor currently as there is no published example of a complete test (one where almost all the ingredients are identified). It is necessary to add bit A from one lab test to bit B from another test, to get some kind of idea. We have a very good idea of what will be in the vapor because it should, basically, be what is in the liquid. Some materials may not make it into the vapor though; but unlike cigarette smoke, nothing new should be created. The main difference will be in the percentages seen.

    The best public results we have so far suggest that there is far more water and far less PG or VG in the vapor than exists in the refill liquid, and that the flavorings remain approximately constant. There is a higher percentage of flavoring in most liquids than people realise.

    Since we know what the implications of inhaling (pure) PG, VG and nicotine* are, it follows that the issues are going to be mainly with the flavoring. Thus far it looks as if the mainstream vapor from a typical e-cig refill is 66% water, 3% PG, 1% VG, ~1% nicotine, and the rest flavoring. That means up to 30% flavors.
    *Inhaling pure PG or pure VG or pure nicotine is likely to have very little implications for health, except for a small number of individuals. The problem (if one exists) is that it is extremely unlikely that all offerings on the market are pure.

    Looking at the 'best guess' percentages as above, there is a lot of flavoring in there. It is impossible to say if this is correct without a lot more data, but it seems that at least 20% flavor in the vapor may be quite normal. Ideally, you would like to be assured that those flavors are safe to inhale. Unfortunately, we are on the bleeding edge here, and no such statement regarding safety could be made. In fact it seems likely that some flavors are going to be found toxic to a greater or lesser extent. We already know this is possible because we do have data on one, diacetyl, which can cause severe harm (although we don't know what quantity would be needed to cause x amount damage in x number of years). There is a theory that every molecule of diacetyl destroys a cell of lung tissue, and since like brain cells these are not repairable, it is of concern.

    Anyway, if some flavors can be tested, and if some vendors can test their finished retail product, that would be about the best we can expect for now. In the end it depends on the trade. If you want government to do it they only do such things, normally, as a result of strongarm regulation.

    ECITA, the trade association in the UK, are now testing liquids (they bought their own GC-MS machine), but it will be a while before they have the resources to test vapor. Testing multiple vapor samples is nowhere near as simple as testing cigarette smoke, which is why every single test so far published (and also one or two unpublished) has failed.
  15. egodzilla

    egodzilla Senior Member ECF Veteran

    Jan 12, 2012
    Dear roly,

    thanx again for your extensive answer ... It is really reassuring to meet benevolent people like you who take their time to help nubs like me ... I guess the companies who have the $ to finance the test are mainly hardware companies who certainly don't need those ... Most of the juice companies seem much smaller ...

    I certainly agree with all your claims. I am also happy that we have intellicig and FA who seem to be the pioneers of our mental ease ...

    But another thing: you are saying that 30% of the vapor are flavors? Even when the flavor represents a much smaller portion of the liquid it self?

    That is interesting ...

    Anyway, thank you again for your contribution.
  16. rolygate

    rolygate Forum Manager Admin Verified Member ECF Veteran

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    Sep 24, 2009
    ECF Towers
    It is impossible to say exactly what the percentages are, until we have a lot more data - several successful, full tests of different brands.

    However I wouldn't be surprised if flavorings are a higher proportion than might be expected. One reason for that is because e-liquids are more heavily flavored than people think. If you DIY then you can find that you need to go to 40% flavoring in order to replicate the flavor strength of some of the commercial liquids. I doubt if there is anything much out there under 25%.

    Firms such as Intellicig (and Decadent Vapours for some of their mixes) who use minimum amounts of known safe flavorings get criticised for weak flavor, so it's obvious that many buyers want very strong flavors. But it's probably hard to get strong flavors with less than about 30% flavoring, and there is also an argument that the 'best' flavors aren't the safest.

    Some of the ingredients in the liquid don't seem to make it into the vapor at the same strength, but this may not apply to flavorings. So all in all it's possible that flavorings will be the largest component after water. It's just something to think about if you are going to vape 4ml a day for the next 20 years. I don't see any major issue with inhaling pure VG or PG or nicotine, it's all been done before over long periods, and we can see from the partial vapor tests we have that the end-user percentages in the vapor are quite small compared to the water content.
  17. egodzilla

    egodzilla Senior Member ECF Veteran

    Jan 12, 2012
    Luckily I only smoked Intellicig and DV juices so far ...

    They are strong enough for me. I don't need to replicate a plum, I just eat one if I want that ...

    So, basically what you say, even if the liquid is mostly PG or VG the vapor mostly turns it to water? Sounds like a good thing. And yes, the flavors probably contain stuff like etheric oils ... Still FA tests are at least partially conclusive if not for else, for the comparison with the tobacco cigarette ...
  18. Penner

    Penner Senior Member ECF Veteran

    Feb 8, 2011

    Decadent Vapours are only in the UK. I'm in the USA :(
  19. Hiryu

    Hiryu Senior Member ECF Veteran

    Jul 3, 2011
    Wrong, Penner. Liberty Flights carries Decadent Vapours e-liquid in their US portal.
  20. Penner

    Penner Senior Member ECF Veteran

    Feb 8, 2011

    Thats great, thanks for sharing. The problem I ran into is googling Decadent Vapour, went to their site, & no USA reseller was listed.
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