I have a sri 310mm that is factory preset for cannabinoid testing but I need to expand the program for terpenes. Any help would be appreciated.
Sounds like you need a smidge more than that.
You really need to understand the software you’re using. Which SRI is not great a documenting.
Where are you located?
Willing to buy a clue?
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Take the time to watch all the videos from SRI. They highlight more than what is simply in the title of the video.
That said, I’m a fan of SRI and happen to just be using my system currently. I’d like to see them continue to grow so here is your spoon:
‘Edit > Channels > Temperature’ will get you where you want to be using peak simple.
SRI provides a base set of temperature files (.TEM) with clear naming to get you started; tweaking as needed based on your column and target separation.
SRI is also extremely responsive; I usually get an email back within an hour or two and they can help get you setup over the phone. I would never hesitate to reach out to them but again, if you would prefer not to and have a go on your own, I can’t stress enough:
Take the time to watch all the videos from SRI. They highlight more than what is simply in the title of the video.
Also, if you’re going to be turning the temperature up beyond standard, remove the Hayesep column. I forgot the max temp they can run but I don’t think its much beyond 240 or 250. This shouldn’t really be a problem if just looking to add terpenes to your current SOP.
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Thank you for the info! I have been through their videos and they are really helpful. Also, Hugh has been more than generous in answering my questions even though I bought the unit used.
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Possibly. I want to get the basics nailed down and then might need a consult to perfect things. Hugh actually just emailed me the specific answer to my question… so that was awesome!
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I agree with everything you said. I thought I might add that there are TONS of documents on their website under document downloads that have loads of good info. I have been trying to digest more from their videos and documents instead of just calling them because a lot of the issues I have called them about has been in those documents. That being said, Hugh has been incredibly helpful on the phone answering my stupid questions. I appreciate that they take the time to answer them fully and don’t brush me off for not knowing my ass from a hole in the ground when it comes to the GC.
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I’ve had the same experience.
@srihugh1 has been a huge help to me over the years.
The first five were supporting a machine we purchased used, and at least one of the two I’ve currently got access to was used.
Having been playing with the software for almost 10years at this point I’m beginning to get the hang of it.
Just wish I didn’t have to run windoze to use it…or could access the win7 VM I ran it under for years.
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If you try to test for terpenes with liquid injection, you’re gonna have a bad time.
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I think what @TheGratefulPhil is trying to say is that liquid injection is not the best for things that are volatile at room temperature.
You should be looking at headspace - which does a gas injection at specific heat and with specific volume.
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What @Cassin said—you really need an autosampler with headspace capabilities to adequately test for terpenes due to their volatility relative to cannabinoids which essentially have no volatility at room temp.
Edit: also, with headspace you can test for residual solvents!
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you can absolutely generate a repeatable “terpene profile” using a liquid injection.
It should be more quantitative than a manual headspace injection.
the terpenes WILL dissolve in ethanol.
they will also fly in the GC however you get them into the injector.
given that they are in your matrix at 20-200 fold lower concentration than the cannabinoids, you have to load more (I used to do 1g flower rather than 100mg). [THIS is where just taking the volatiles helps…]
figuring out what the various peaks actually are? that will require a liquid injection of your standards.
I figure that the Edibles analysis using new SRI GC configuration backflush capabilities would allow backing the cannabinoids out rather than driving them (and the gunk that elutes after the cannabinoids) at your injector. haven’t gotten around to trying it yet.
you will certainly loose some (presumed “terpene”) peaks to your (massive) solvent peak…starting at 30-50C helps there.
not saying that headspace isn’t the RIGHT tool. just that “run what you brung” will get the job done.
HPLC terpene analysis: https://www.tandfonline.com/doi/abs/10.1081/JLC-120014270
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From personal experience, it was a lot more of an analytical development headache than it was worth—but you’re right that it could be done, without a doubt.
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We are convinced that liquid injection for terpenes is better than headspace because:
- You are already doing a liquid extraction for the cannabinoids which also extracts the terps. Why do a 2nd analysis when you can do both terps and cannabinoids with one liquid injection. See this chromatogram. http://www.srigc.com/cn/downloads/333/Terps+THC.pdf
If you use a column like the 30MXT502 1micron film there is no problem to separate the most volatile terp ( pinene ) from the solvent. - Headspace results in vastly less carrophyllene ( high boiler ) compared to pinene ( low boiler ) in the headspace and when you withddraw the headspace from the bottle the carrophyllene condenses in the syringe so it very diffficult to get the sample from the bottle to the GC without losses of the high boilers. You could spend $50k+ for a hot headspace unit which overcomes this problem but SRI is all about doing things affordably.
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This method is developed on a RTX-50 column. Seems do-able. I now have a headspace sampler (still in crate), so I guess in time we’ll find out.
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Thank you!!
Did you mark that copy up?!?
@Phattfruity: guessing you probably have more clues than you know what to do with right now.
Come back a share your voyage as you get this figured out.
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Lol whoooops, I didn’t even check it before throwing it out there
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I love all the information this group shares! Thank you!!!
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