LC isomer (chiral) separation methods

The normal LC method for potency (~78% ACN + acidic h20 on a C18 column) is obviously flawed for analysis of delta-8-THC products. In many cases it does not even resolve D8 from D9 reproducibly. There are multiple byproducts that elute around the same time as D8/9, and probably more enantiomers that directly coelute on C18.

So we are looking for current LC methods that may be a better alternative to the normal C18 methods. Specifically ones that would separate the THC isomers and chiral byproducts under HPLC conditions.

Heptane:ipa:meoh on amylose1 column
https://future4200.com/uploads/short-url/jxv7NC0UZgszC917S7b7tomqFkJ.pdf

ACN:h2o on amylose1/3 column (shown with CBD isomers only)

Please link to other applicable methods if you know of them. Would love to see a D8 product ran on a chiral method.

6 Likes

Someone linked this well laid out paper in another thread within the last few days:

validated chiral HPLC.pdf (2.4 MB)

1 Like

Although those columns are by no means cheap ($2,200)

1 Like

those were my initial thoughts as well

anyone got a plug for this type of media?

That was the first method I posted. But yes the columns are expensive! You can get cheaper ones at phenomenex, this one should suffice at $1,200.

1 Like

Hell yeah, thanks for the tips dawg

Let me see if I can do this right… @kcalabs @analyte @MagisterChemist @Dr_Jebril

Maybe some of these folks have input on a chiral LC method?

2 Likes

Dear Mr Labdog,

No Im sorry in my case I don’t know much about LC methods for cannabinoïds (or other chiral things). But Im willing to buy an hplc during this year. So Im interested in the conversation.

3 Likes

If i had a chiral.column, i could play around on my hplc and create a method. I don’t have much free budget for a project like that though.

We have a couple chiral columns that can be used for R&D, but to buy a new one for production they cost $2500+. I don’t see an economic driver to do such testing now, but I know we’ll be ready out of the gates if it’s required in new regs or demand increases in the market.

We’re looking into options away from having to use a chiral column.

You could use your chiral column to identify if there are non-cannabis terpenes added. This will likely be a regulatory requirement in many states within a year, maybe two.

2 Likes

What are the scenarios where people expect distinguishing enantiomers to be important? Do you realize chiral chromatography is specifically for enantiomers not just generic “isomers”?

2 Likes

I’d guess mainly for conversions (CBD to D8 and the likes) I cant think of many other situations that enantiomers would get made in the normal pre or post processes most folks do, although the terpene testing to rule out non-cannabis additives mentioned above is somewhat intriguing

What enantiomers would be formed in d8 synthesis?

1 Like

@MagisterChemist Under CFR, chiral drugs must be analyzed to determine the presence of enantiomers, diastereomers and the like. If we expect to continue producing these compounds when they become federally legal and the FDA has control, then we need to preemptively develope chiral methods of analysis.

Now, with the current arguments and fear-mongering regarding “unknown isomers” in isomerized products, it would behoove us to begin separating these to at least identify them for study.

So those are the 2 main reasons I see for performing chiral analysis.

6 Likes

Supposedly, yes, in some D8 syntheses, there are other stereoisomers created.

2 Likes

Certainly, but a stereoisomer isn’t necessarily an enantiomer.

I totally get the concept of, we should check it out out of an abundance of caution. I’m just curious if we have any mechanism-based reason to expect we’ll find any.

1 Like

Yeah I think it’s really just going to be mainly to cover your ass rather than practical reasons. I think it will be like most industries where it’s a standard to be able to prove where your materials originated, naturally, synthetically, or one of the different classifications in between.

Products made by a conversion from plant material such as hemp can be legally recognized as natural (in the US) so radiocarbon dating and chiral separation would be necessary to prove it was made using naturally derived carbon sources. I think the important thing to note is that we will inevitably see cannabinoids made from petroleum products, maybe not from those of us here but that alone will require a standardized method of differentiating origin for everyone.

I don’t think any of us really know what we will see on just simple conversions like CBD>D8 but starting with a synthetic terpenoid like in a lot of the earlier literature will probably have a greater demand for this level of testing. So if some cannabinoids are being made this way, it would be common practice for everyone to follow the same testing methods. Just like photon said, if we plan to be able to take part in this industry for much longer than it’s in our best interest to have all of these bases covered.

3 Likes

I dont see any obvious mechanisms for making enantiomers but weirder things have happened and I think it would be good to check. Also I am thinking the chiral column may offer a good orthogonal method of separation for the isomer byproducts (enantiomers or not) vs c18… may resolve d9 from d8 better than c18.

So I am looking at it as a possible d8 conversion specific method. Since the normal potency LC method is kind of crap with those conversions. Just need the setup to not be such a pain that it is uneconomical, but looks like it may just actually be a column switch and even use the same MPs.

Still sourcing methods before making a decision but an extra $1200 column is not too bad if that is all we really need.

2 Likes

If that’s your main goal you may want to give phenyl columns or something similar a try. Probably could get a few for the price of one chiral column.

1 Like