Vapor composition

[tor]

Hello,

I would like to know exactly, if you know of an experimental protocol who tried to analyze precisely the composition of the vapor as a function of temperature ? It would be very interesting to have such a curve, that is to say : amount of product in % (for any chemical that is released during the vaporization process : THC, CO2, CO, H2O, whatever) vs Temperature.

Do you know any serious study on the matter ? It would be really important to me to have a scientifical assessment of what is made the vapor.

I know this has already been done for tobacco smoke with great cares and details, if such a study could be performed for vaporized cannabis, it would be so great !

Happy vapes !

 

[Seek]

There could be curve like that only if you assumed so many variables as constant. Because vapor composition is not a function only of temperature, it is way more complex. Pressure, uniformity of heat, conduction/convection/IR, airflow, quality/dryness/composition of loaded herb, herb chamber design, materials in the airpath, how long it has already been vaping and how long the vapor was stored, and more is also affecting the composition of vapor so if you wanted a curve liek that, you need all these things (and even more, it's physics, almost everything takes effect) assumed and constant. That is like impossible only because of the time factor. Because of that that curve need to be at least two-dimensional and it would still suck as it would only show measurement of one specific vape/herb/load/technique used.

 

[tor]

I found the wikipedia page on this matter [1] fairly complete.

I found a paper "Cannabis vaporizer combines efficient delivery of THC with effective suppression of pyrolytic compounds" [2]. I will try to sum it up here in a few words.

Summary
The researchers used several 0.2 g weed samples, with the same THC concentration (4 %) and they compared efficiency of burning the weed against vaporizing it. They repeated the test with 3 samples for vaporization and combustion.

The burning has been made using a glass pipe, and the vaporization in a volcano. They studied first by liquid chromatography, the efficiency of the two process.

Total combustion of the sample is extracting 80 % of the THC, while the vaporization in three ballons for each of the sample has a mean efficiency of about 50 %.

Also, they noticed that the discrepancy of the efficiency is large with the volcano, because on one sample they had 36 % of efficiency and on the other they obtained 61 %. They concluded that tirring the sample, the concentration amount in THC of the initial sample, and many micro-factors could influence a lot the efficiency of the vaporization.

They studied the vapor produced and compared it to a combustion process by using also a gas chromatograph and mass spectrometry. It shows that a noticeable interest of the vaporization vs combustion is the quasi absence of PAHs (Polynuclear aromatic hydrocarbons) while 111 aromatic compounds are found in the smoked marijuana.

However, this study does not report about toxic gases with low molecular weight, such as ammonia (NH3), hydrogen cyanid (HCN), and carbon monoxid (CO), which are produced when smoking the marijuana. We now only that a qualitative reduction of carbon monoxid appears when using vaporization from this article.

[1] http://en.wikipedia.org/wiki/Vaporizer_(cannabis)
[2] http://www.maps.org/mmj/Gieringer-vaporizer.pdf

[...] assumed and constant. That is like impossible only because of the time factor. Because of that that curve need to be at least two-dimensional and it would still suck as it would only show measurement of one specific vape/herb/load/technique used.

Well, this is a fact that vaporization is not well known. I think it is somehow a pity that so much people are enjoying vaporization without knowing exactly what vaporization is introducing into themselves. I am myself rather convinced by the benefits of vaporization, but if I'd prefer to have precise informations. I am confident anyway that vaporization is much better for health than smoking.
Cheers.

 

[Seek]

The researchers used several 0.2 g weed samples, with the same THC concentration (4 %) and they compared efficiency of burning the weed against vaporizing it. They repeated the test with 3 samples for vaporization and combustion.

First two constants assumed: 0.2g, 4% THC. No more info about the herb, so we don't know if it has any nasty stuff in therethat could get vaped.

The burning has been made using a glass pipe, and the vaporization in a volcano. They studied first by liquid chromatography, the efficiency of the two process.

Using a Volcano set lots of another constants, as the vape materials, heater design, chamber design, convection, bag fill (that is also smoothing the time factor, vapor in bags get combined-averaged, but with a direct draw, you find every next hit different). They don't say how long the vapor was in bag, some components can condense faster.

Also, they noticed that the discrepancy of the efficiency is large with the volcano, because on one sample they had 36 % of efficiency and on the other they obtained 61 %. They concluded that tirring the sample, the concentration amount in THC of the initial sample, and many micro-factors could influence a lot the efficiency of the vaporization.

This is what I'm talking about. Even scientists can't get consistent results with a high-tech device. There are so many variables.

Well, this is a fact that vaporization is not well known. I think it is somehow a pity that so much people are enjoying vaporization without knowing exactly what vaporization is introducing into themselves. I am myself rather convinced by the benefits of vaporization, but if I'd prefer to have precise informations. I am confident anyway that vaporization is much better for health than smoking.
Cheers.

You can be confident, that with a quality vape and temperature low enough you get absolutely non-toxic vapor with goodies only. These variables I mentioned have influence mostly on the ratio of goodies present in vapor and the potency. Only variables like unsafe materials in airpath, too high/badly controlled temperature, or severely not uniform heat distribution can ADD new possibly harmful substances to the vapor. All these other variables just gives you hits inconsistent to some degree.

With smoking, there is scorching that breaks down the matter making new subtances and pyrolysis which makes even more. When you get a vape hit and nothing gets schorched, these two events don't happen. So you couldn't get any substance that was not present in the herb, like smoke has a ton of them. You got cannabinoid, but many variables affect how many and in what ratio.

 

[tor]

First two constants assumed: 0.2g, 4% THC. No more info about the herb, so we don't know if it has any nasty stuff in therethat could get vaped.[...]Using a Volcano set lots of another constants.

Well, first point I agree with you basically. IMO, this is best for all publications and researchers working on vaporization to use a reference frame to work within. However, the volcano itself does not give reproducible results from what I read in this reference [1]. Too bad

A question I have in mind, is, what actually creates the difference between the thick vapor and the « not thick vapor ». How the vapor becomes thick and why does it become thick are question of interest, because it would allow the user to control its vaporizer at glance.

I was also astonished because it appears that smoked MJ produces 20× more ammonia than smoked tobacco. Do you think ammonia could appear in vapor ? At the best of my knowledge, no study of the MJ vapor has looked for ammonia.

Also, I thought of a more consistent experiment to extensively study the composition of vapor for an uniform weed sampling from 50°C to 500°C. If I had the material at hand, I'd get a lot of citations because I see there is a few academic studies on this question.

Let me tell you the idea : it would consist of a heating element that could ensure a air flow temperature from 50°C to 500°C. Then, you could imagine that you use a well grinded 100g weed sample with uniform THC distribution, and you could perform an exhaustive study of the formed byproducts along with the vaporization temperature. Temperature would be measured on the weed sample in permanent regime, and the weed would also be put in the air flow in permanent regime, and the vaporization would occur only for a limited amount of time (let's say 100s). Then the hot air would be analyzed qualitatively and properly for every gas (O2,CO2,CO,NH3,PAHs,...) by a mass spectrometer. If I had money and permissive legislation, for sure I'd make the test.

[1] http://dx.doi.org/10.1002/jps.20574

 

[Seek]

Measuring vape hits will be always inconsistent. But there are some "laws" of release.

When you start hitting a vape at any temp, first there is water being evaporated.

Then aromatic flavonoids releases.

Then it decarboxylates and releases CO2.

Then parts of herb that actually reach 130-185 °C slowly release thc. Speed of release is dependent of temperature (higher temp - faster), pressure (lower - faster), airflow (convection: higher - faster; conduction/IR: slower - faster), how the herb is already spent (fresh herb releases more thc in one hit than almost spent), uniformity of heat/stirring (more uniform/stirred - faster), if it's packed etc. Higher temp cannabinoids would need higher temp to achieve the same mechanics of extraction.

If any part of the herb get too hot it scorches, it's matter breaks down and released harmful substances. This is what we don't want to achieve with a vape.

 

[pakalolo]

Then aromatic flavonoids releases.

Flavonoids provide colour and serve a few other functions, but not aroma or flavour. Terpenoids are responsible for aroma and taste.

Combustion occurs at a fixed temperature and therefore is much easier to study. As you point out, vapourization occurs throughout a range of temperatures and the results vary depending on the temperature, even if all other variables are held constant.

 

[tor]

By the way, I found a thread about ammonia in vapor : http://fuckcombustion.com/threads/vaporization-health-research-real-facts.1597/

enjoy this thread is very useful.