SOS! GC-FID and HPLC-DAD sample prep for potency (ALL MATRICES!)

Hi Friends, SOS!!!

We are a new in-house analytics lab in Oregon. Currently running potency on GC-FID with OpenLabs CDS Chemstation Edition. Eventually will be getting an HPLC to test the acid forms. There are a few of us chemists here from different backgrounds who have run these instruments before, but limited experience on method development.

There’s a ton of information online about the acquisition method as far as instrument parameters…but limited information on the initial sample prep math and inputting this into OpenLabs (sample amount, multipliers, dilution factors). Especially when sample amount box is unitless (ppm, mg, ug…!!!)

We were wondering when we are designing sample prep methods for different matrices, what are the things that need to be considered when comparing against %ESTD? Our curve runs from 0.5-250 ppm. (Open to using internal standards).

-How many mg to weigh out in how many ml solvent. Accounting for density of MeOH?
-Need to figure out how to report in % for flower and concentrate but mg/g for our edibles, topicals, tinctures, bath salts, bath bombs, pills etc…

For example, I know we have:
~20% flower
~70-80% concentrate
3g gummy at 10, 20, 40 mg/g.
3 oz jar of 100:100 mg THC:CBD topicals
15 g bath salt serving 1:1
1:1 bath bomb
Several tincture ratios…

What approach would you take to figure out the best sample prep MATH? We build some sheets on excel to calculate mg/ml, ppm. We can figure out homogenization but tips here would also help.

If anyone has any methods to the madness (literally) please share!

#sampleprep #hplc #gcfid #openlabs #methods

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Welcome!

Sounds like you need a consult. DM me. I can help you.

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Did you know - that the methods for these things are now available as compendial international standard test methods. Including sample preparation and sample collection standards by ASTM.

You should get those standards from ASTM and the test method from AOAC. Its got lots of good info, including all the papers leading up to how they decided to do this, and the method validation parameters used.

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That ASTM and AOAC is just BS fluff by armchair jerkoffs. If you read it… it is just telling you guidelines to meet… “you will meet these acceptance criteria” its all BS. And they are borrowing from envirnomental sampling and pharma regs like its a damn candy shop… round hole in a square pig if you ask me.

You will get nothing of substance from those “methods”. The validation parameters are for the instrument and not really the extraction. And they surely do not give any fs about throughput or anything that really matters in a production lab.

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Having actively participated in making these methods - I think you are behind on the details, mate.

They are not just “acceptance criteria” statements anymore. I get the feeling you haven’t read these? Or haven’t looked at them in the last couple of years?

There are very clear standards for how to sample (in the field and indoors) to minimize variation and how to appropriately homogenize samples before getting to the lab.

There are very clear standards for how to homogenize samples once they are in the lab. And for how to extract (two methods are provided, they both work - I’ve used them both and they are better than many of the other things I’ve done in the past).

And their methods for how to run HPLC are very clear. The updated method for running GCMS I think could still use some tweaking, I’m not happy with it, and have submitted comments to have it updated. But it clearly defines elution schedule, calibration curves, places to purchase reference standards, compatible types of internal standards, and expectations based on hundreds of labs submitting validation data, so you know what to expect.

No one writing compendial methods give too many fucks about throughput. They give lots of fucks about accuracy, precision - making sure the science is repeatable - and making sure everyone does it the same way. So that every time a sample is tested - by every lab that would do that test - your sample result is as close to the same as can be had with currently available technology. That’s important when consumer groups are testing your stuff - or when regulators can come in and take your retains and force a recall if your test results are different than theirs. (This happened recently and was in the news…so working to prevent it at the source is important, IMO.)

There’s a reason labs get a bad name all the time - because people still seem to not care about the right things. I’ve been doing this for a long time across many industries. Still don’t know why people want to treat cannabis products as though they are the most innovative thing on the planet.

If it works for hundreds of other plants that get extracted around the world - it can work for cannabis.

If it works for hundreds of thousands of other consumer products that are manufactured around the world - it can work for cannabis.

The only reason this is special is because of prohibition. And the sooner people get on the self-regulating and standardized commodity train the better - because federal legalization is coming and global competition is just around the corner. And then we’ll all be using these compendial methods - just like we do for everything else - because if you don’t use them, you won’t be able to import or export or sell them. :frowning:

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Flower:
~0.5g flower + 5ml ACN:MeOH (1:1) in 50ml conical tube
Add two larger (1/4") BBs. Freeze in -20 to temp. Ball mill cold. Vortex, sonicate at 30c 10+min, vortex.
This is your 1/10 extraction. No factoring for wt of solvent, math is just 1/10 dilution of sample… controlled for actual sample weight of course.

For LC, you would filter a bit out and dilute to the desired ppm range (probbably aim for like 1/2000 dilution if you are testing good flower). Dilution solvent should be what your LC is running at initial time (aka 50/50 acn/h2o). At 1/2000 fold dilute (using your ppm range)… your loq is 0.05% to 50% in sample… not bad if that truely is your validated range.

For GC… ? id like to hear it really.

At 1/2000 fold dilute

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Can you guys post links to the ASTM and AOAC methods, please! Thanks in advance!!

Describe the two extraction methods, give me a skeleton. What solvents are they suggesting to use? What is their initial sample extraction at?

I dont believe any bunch of bloated armchair people that are not on the ground doing the work should be trying to standardize testing methods. I do believe we need to standardize testing methods to an extent but not by these jokers.

And really nobody in authority cares about potency numbers, its just a bunch of stoners lieing to one another… why would they care? They got their checks already. If a lab has motive to give true numbers, its not that hard, if a lab has motives to give inflated numbers, its not that hard. Just really matters the motives, not all this “standardization” by some 3rd party chemists, wont help get true numbers untill the motives are worked out.

I couldn’t disagree more. “Borrowed from environmental sampling and pharma regs” — More like created by the same experts that made them in the first place. Are you under the impression that ASTM/AOAC is exclusive to cannabis analysis?

This I agree with, 100%. As much as I hate to admit it, sample preparation methods for cannabis analysis seem to be highly commercialized. Especially when the instrumentation/consumable manufacturers are so heavily involved with aforementioned AOAC/ASTM methods.

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Why do you think these are not people on the ground doing the work? I know these people - I am these people. We are all boots on the ground - working in the industry AND volunteering our time and sharing our IP with everyone that isn’t volunteering to get us over this self-regulated hump and have standardized methods for everyone to use.

The methods that are listed for sample prep are not that different from what you posted up above. The amount of the flower is more (and there’s a paper that discusses why) and there’s also a paper comparing different extraction solvents and discussing why they picked the one they did (cost, availability, and recovery percentages are also discussed).

Other people who are working on this run huge facilities testing thousands of products in states across the country. We are the chemists and the quality control technicians and the statisticians and the growers and the processors - all working together on these things.

If you hate our work so much - you should come and work with us on it. This is all volunteer work mate - anyone who is interested can volunteer. The more voices the better. You know?

ASTM - List of standards that are active and approved and all the drafts.

AOAC - this is the specific method for cannabis potency in flower and oil - there are others.

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Are you saying subject matter experts in pharma and environmental testing are qualified to create methods by which an agricultural product is judged and marketed? Because that sounds dumb.

Cannabis is not in these guys’ wheelhouse and that should be obvious. The folks the ASTM and AOAC put on this have no experience standardizing an ag product and they are treating it like a pharma product. It is more akin to a food or dare i say a vice product… maybe like tomacco… you ever seen tomacco testing like this? Didnt think so.

Why would I want to contribute to a matrix of handcuffs? And for free? No thanks, I’ll take dynamic and flexible method development over what you are selling. And you are literally selling it because that method you guys all made for free is now behind a paywall. Great way to do business, are we back in academia now… all working for free and kudos on the CV?

Again lay out the two methods and let us judge them. This is not AOAC/ASTM marketplace blog.

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Judged and marketed? Not sure where you pulled that from… The focus here is standardized testing methods, not how a product should be treated, perceived or classified.

Subject matter experts in those fields are definitely qualified to create methods by which an agricultural product is analyzed. You realize that the AOAC and ASTM are both USDA/FDA recognized sources for analytical procedures, right?

What are you getting at? Who would you recommend for standardizing these testing methods?

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We would like to help standardize them, but how can you standardize when there is no governing body for the laboratories?

Everyone is welcome. Please come and join us, that link I gave gets you direct to the committee and its only a short form. We have our big committee meetings the first full week of July! ASTM and USP and AOAC have been doing this stuff for years. @analyte is right that the FDA/USDA (and many state regulators as well) look to these existing international standards companies for how these things should be done. These organizations set the standards for industries around the world, ours will not be different.

Infrastructure costs money to maintain. I’m not above volunteering to help everyone level up together. Anyone who says they want the industry to be better - but isn’t willing to work towards standardization that helps us get ready for the regulated space… I mean - help us help everyone else.

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Most of our chemists are AOAC members and we have a representative in CASP.

The issue is even if we follow the same standards there are still others that won’t. Standards are great, but when much of the industry doesn’t understand the reason for testing and when to test there will be a lack of useful and traceable data from testing in the market. Then you have labs applying methods that cut costs and quality drops. If we all standardize around the wrong method then that stiffles innovation in a still developing scientific field.

Despite the pessimism I think we’ll get there eventually. Do we all last long enough to make it, though?

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There is plenty of information on this forum presented by myself and others regarding testing of all cannabinoids (including acids) on GC-FID. Take a look around and read up, after that I can answer some questions you may have lingering.

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@Dr_Jebril is also GC-FID and you can search his past comments.

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Curious what amount of time people are using when ultrasonicating their samples? This is probably the longest time I’ve seen mentioned (3 minutes comes to mind) and kinda curious what everyone is doing.

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I know some people on the board who are very well respected chemists. I did not know these were available (most is proprietary that they would help with but can’t). If you have useful information besides your opinion on the chemists pioneering the industry on their own time (Many scientific organizations do this) I’m all ears. If anything I think it makes the data and input more valuable since they aren’t being driven to put something out like a product to be marketed. :slight_smile: