[NorthernLabServices]

Greetings everyone.

I own a medical marijuana testing lab in Michigan. I have a GC/FID set up to analyze the quantities of cannabinoids present in a given sample. I recently was given some samples of glycerin tinctures to test for cannabinoid content. I performed my standard extraction, using approx 100 mg of the sample and dissolving it in 10 ml of methanol and sonicating for 10-15 minutes. The results came back quite low and very inconsistent, even after sonicating the original samples for 10-15 minutes.

The problem is, the patients using these tinctures say they produce the desired effect, so I am forced to conclude that there are more cannabinoids present than I'm able to extract with methanol.

Is it possible that the glycerin has a stronger molecular bond with the cannabinoids and the methanol is not able to pull them off the glycerin molecules?

Cannabinoids are almost exclusively non-polar, and I know that both methanol and glycerin have both polar and non-polar molecules, would it help if I used another solvent that is more non-polar than methanol, like hexane for example?

Any other ideas any of you could offer would be welcomed!

Thank you.

[zaphraud]

Well, considering these compounds were probably produced outside of the regulation of the FDA (a federal agency with little concern over state's rights issues), it is at least worth considering that the samples may contain cannabinoid agonists of a non-natural origin that do not behave in a manner in which your facility is used to handling.

Can't think of a way to answer the question which you actually asked in a manner consistent with the rules of this forum, as it could also be used to concentrate a scheduled substance extracted from an approved mixture. Sorry.

But, since you have access to state-sanctioned supplies, perhaps (with additional approval?) you could calibrate the process against a known concentration in glycerin, by preparing it yourself from known samples and then repeating the test.

[NorthernLabServices]

Well, considering these compounds were probably produced outside of the regulation of the FDA (a federal agency with little concern over state's rights issues), it is at least worth considering that the samples may contain cannabinoid agonists of a non-natural origin that do not behave in a manner in which your facility is used to handling.

Can't think of a way to answer the question which you actually asked in a manner consistent with the rules of this forum, as it could also be used to concentrate a scheduled substance extracted from an approved mixture. Sorry.

But, since you have access to state-sanctioned supplies, perhaps (with additional approval?) you could calibrate the process against a known concentration in glycerin, by preparing it yourself from known samples and then repeating the test.

Ok, thank you.