[Chimera]

That's nonsense that UPLC-MS is the best method for terps, we've run a fully validated protocol with spike recovery using standards and GC-FID is the method. And we do have UPLC and MS, but MS is not needed unless you are trying to identify compounds for which you don't have a standard. Which method do you use in your laboratory OO, do you use UPLC-MS? Or are you simply speaking generalities?

As far as genes regulating terps, it's true that genes control the terpene finger print (overall profile), but specific terps fluctuate to a degree depending on epigenetic factors.

Even on a single table, where all plants are fed the same nutrients, there is some variation of levels of specific terps, whereas other terps are more stable.

You can't gain these results from a few tests, the true story comes out when you test batches of the same flowers grown in standardized conditions, time and time again, and start to compare results of the same cultivars between runs. Overall plants will retain the same fingerprint, but do show some variation between the relative components.

It's more about environment and consistent conditions- light exposure and intensity is just a single factor. Also running a single sample of bud from a crop is not really indicative of the average of the flowers across the whole crop. Testing can be manipulated if a sound sampling protocol and validated methodology is not used, so beware of this when interpreting single results from a lab... there is much more to the story.

-Chimera

[Only Ornamental]

Originally Posted by Chimera

That's nonsense that UPLC-MS is the best method for terps, we've run a fully validated protocol with spike recovery using standards and GC-FID is the method. And we do have UPLC and MS, but MS is not needed unless you are trying to identify compounds for which you don't have a standard. Which method do you use in your laboratory OO, do you use UPLC-MS? Or are you simply speaking generalities?...

My answer was a response to FatherEarth's statement who's looking for a sophisticated no-heat method for, as I understand, also unknown terpenes (could be sterols FWIW).
Regarding known mono- and not too highly 'functionalised' sesquiterpenes, you're mostly right and regarding cannabis, where I have no personal experience with, I believe you instantaneously that GC-FID is a better way to go in many aspects (ease of manipulation, cost etc.).
Certainly, everything highly depends on the column but also all the other instruments and methods used, MS isn't MS. Besides, the commonly used LC columns aren't usually that great for small hydrocarbons and I wouldn't start with UPLC for those, it certainly isn't the smartest idea and there has to be an MS coupled to it; coupling two instruments is also more work and effort than a GC-FID that 'comes in one piece'.
The labs I work/-ed with use/-d UPLC-MS as standard for screening, profiling, and 'omics' whereas GC becomes more and more secondary or even obsolete. Though, essential oils aren't usually on the menu but if so, then GC-FID was/is still valuable.
There is not one perfect method for everything and there's always an exception for every rule...

I didn't specify that my response was hypothetical as I was under the assumption that this is quite obvious... guess it wasn't. Thanks for pointing that out!

[tropicanna]

Chimera is right...UPLC is for heat degradable organic compounds such as THCA (acid) since GC MS decarboxylates the acid to THC.

[tropicanna]

Ohh snap!! Just realized this is Chimera the breeder who popped into the conversation. What a coincidence...got some oxacan highland mexican gear heading this way as we speak.Can't wait to see how it performs in my island. Back in the 90's and till the early 2000's much of the cannabis available here was outdoor "bricks" imported from mexico. I miss the giggly,uplifted,cerebral,long-lasting buzz and the notes of spice, roasted coffee and berries that predominated during those days. Now a days it all seems to have been replaced by the sleepy head kush hybrids grown locally.I am all for variety, so hopefully these can spice things up a bit. Kind regards, and thanks for taking your time to put your "gold nuggets" worth of knowledge.

[Bubbleblower]

Why do most people want to discuss theory and not how to grow the best weed in reality?

Probably the biggest reason for that is they don't think they can anyway.

It's a selffullfilling prophecy.

[Sam_Skunkman]

Hey Chimera,
I was talking with a proton NMR guy who says that proton NMR is the best way to determine terpenes as all the analysis is done with zero sample destruction and all the terpenes retain their original forms while a GC alters the forms into other compounds? As I have told you we used GC-FID for 2 decades for terpene analysis.
I told hin that a GC is closer to people smoking the herb or resin, and that is what we wanted. If heat alters the analysis then heat is altering what people smoke, not many people consume Cannabis in a way that does not use heat. People use to also tell me to use HPLC for Cannabinoid analysis but I was more interested in the neutral forms of Cannabinoids not the acid forms and neutral side by side.
I understand that folks that eat Cannabis products are interested in the neutral forms and the acid forms.
-SamS

Originally Posted by Chimera

That's nonsense that UPLC-MS is the best method for terps, we've run a fully validated protocol with spike recovery using standards and GC-FID is the method. And we do have UPLC and MS, but MS is not needed unless you are trying to identify compounds for which you don't have a standard. Which method do you use in your laboratory OO, do you use UPLC-MS? Or are you simply speaking generalities?

As far as genes regulating terps, it's true that genes control the terpene finger print (overall profile), but specific terps fluctuate to a degree depending on epigenetic factors.

Even on a single table, where all plants are fed the same nutrients, there is some variation of levels of specific terps, whereas other terps are more stable.

You can't gain these results from a few tests, the true story comes out when you test batches of the same flowers grown in standardized conditions, time and time again, and start to compare results of the same cultivars between runs. Overall plants will retain the same fingerprint, but do show some variation between the relative components.

It's more about environment and consistent conditions- light exposure and intensity is just a single factor. Also running a single sample of bud from a crop is not really indicative of the average of the flowers across the whole crop. Testing can be manipulated if a sound sampling protocol and validated methodology is not used, so beware of this when interpreting single results from a lab... there is much more to the story.

-Chimera

[Only Ornamental]

Originally Posted by Sam_Skunkman

Hey Chimera,
I was talking with a proton NMR guy who says that proton NMR is the best way to determine terpenes as all the analysis is done with zero sample destruction and all the terpenes retain their original forms while a GC alters the forms into other compounds? ...

Hi Sam,
Out of curiosity, can he do that with a complex mixture of similar constituents and accurately determine their concentration? I mean, theoretically it's feasible (especially with high end machines) and I've seen conceptual work with sugars and phenolics but how does it look with everyday life samples such as essential oils?
It's quite funny that every expert thinks his 'strategy X' is the best; being unbiased in such a situation isn't always easy... (dam, did I just fail regarding UPLC-MS?)

[Sam_Skunkman]

He has worked with NMR for 30 years and says yes. And in solid, liquid or gas state, he can sample them all with no damage or changes to the samples. He also said the peaks will overlap and you may need to use the equivalent of MS to separate them.
Here is a paper using NMR for Cannabis not sure if others posted:

https://cannabisinternational.org/inf...nnabinoids.pdf

My friend says:
The ability to identify the trace components depends on the signal/noise ratio in the NMR. Certain peaks in the NMR correspond to more protons such as the peak for a methyl group which will be three times larger than a peak for a single hydrogen atom in the same molecule. So the larger peaks can be used to id the compound if "you can see the forest thru the trees". Multidimensional NMR techniques can be used to deconvolute mixtures resulting in overlapping signals. Furthermore, NMR provides information on bond connectivity between atoms by looking at coupling between resonances of different spin systems (protons and carbons).

All 80+ cannabinoids and 140 terpenoids, if they are present in the extract or concentrate, will be visible but the level of sensitivity of NMR can be limited due to the amount on the component present and it's relative concentration to the other major components present. That means that there could be a window in the spectrum where a trace component has a peak (resonance) and that single peak could be used to id that particular compound even if the other peaks corresponding to that compound are obscured by that larger peaks of the major components present.



I get the feeling that NMR use with Cannabis is really just starting and folks using NMR will find uses for analysis of certain Cannabis compounds, if that includes terpenes like I hope then I welcome it. To allow the sample to be unchanged by the analysis is interesting.

-SamS

Originally Posted by Only Ornamental

Hi Sam,
Out of curiosity, can he do that with a complex mixture of similar constituents and accurately determine their concentration? I mean, theoretically it's feasible (especially with high end machines) and I've seen conceptual work with sugars and phenolics but how does it look with everyday life samples such as essential oils?
It's quite funny that every expert thinks his 'strategy X' is the best; being unbiased in such a situation isn't always easy... (dam, did I just fail regarding UPLC-MS?)

[Only Ornamental]

Originally Posted by Sam_Skunkman

He has worked with NMR for 30 years and says yes. And in solid, liquid or gas state, he can sample them all with no damage or changes to the samples. He also said the peaks will overlap and you may need to use the equivalent of MS to separate them. That's the interesting part IMO.
Here is a paper using NMR for Cannabis not sure if others posted:

https://cannabisinternational.org/inf...nnabinoids.pdf
They only used NMR for structure elucidation of isolated pure compounds...
My friend says:
...
All 80+ cannabinoids and 140 terpenoids, if they are present in the extract or concentrate, will be visible but the level of sensitivity of NMR can be limited due to the amount on the component present and it's relative concentration to the other major components present. That means that there could be a window in the spectrum where a trace component has a peak (resonance) and that single peak could be used to id that particular compound even if the other peaks corresponding to that compound are obscured by that larger peaks of the major components present.
That's the point I wonder about: What I've seen so far is that it works in theory but the applicability for a specific sample has to be shown first and the way you put it, he hasn't tested cannabis either.

I get the feeling that NMR use with Cannabis is really just starting and folks using NMR will find uses for analysis of certain Cannabis compounds, if that includes terpenes like I hope then I welcome it. To allow the sample to be unchanged by the analysis is interesting.
Likely all published structures of cannabis constituents and most natural compounds have, at some point, been determined with NMR (a few might have been elucidated with X-ray crystallography). I doubt that NMR will become a part of 'lab testing' but things change fast in this environment...
-SamS

Thanks for elaborating!

[tropicanna]

NMR machines are very,very,very expensive, not to mention the helium gas needed to run the damn thing. I don't know of a single lab that does cannabis analysis that owns one of those.Besides, NMR is used to determine the electronic environment of specific nuclei in order to elucidate structure. You might find them in academia research labs and pharma industry labs, not in lab testing for cannabinoids and terpenes. Terpenoids are volatile,meaning they go into gas phase at relatively low temperatures but they don't degrade under GC conditions.They boil off and evaporate and in the gaseous phase then they get separated by their affinity to the stationary phase which is the column they travel through.On their way out they are broken down into fragments and the ions are identified by their mass to charge ratio.