Working with some Process/Analytical Chemists from Biotage this week. Anyone have any advanced questions for me to ask?


So, I am a quick learner and have finished pesticide remediation R&D with the chemists today. I have all tomorrow to talk and work with them. We will be looking at how high we can load the magsil/florisil pr columns I packed. I am still deciding if we will be going with silica or magsil. I have quite a few clients/friends wanting larger scale-outs of these purification systems. In about 2-3 weeks I will have a solid answer as we will be optimizing our purification strategy/method/gradients. This works to clean the pesticides, and does it super freaking quickly. If I load a 60 gram florisil column with 60 grams of extract, I can flash it in about 5-8 min max. We can easily scale this once we have the optimizations done.
Still looking at larger columns, I discussed the idea with Biotage today, and got the run down on their FLASH 150/400 systems (ideal for mostly reverse phase cannabinoid isolation, leading to isolate). We talked about columns for pesticide remediation, and its a tough one. Either I go with re-packable GE or PALL columns (like $20K for a good sized one), or I take a chance at designing my own. I cant find a way to ensure the pressure is evenly distributed in the column. Work in the lab today led to some channeling during a test, and I would like to avoid that at the large scale.

If anyone has any questions about advanced chromatography topics they can think to ask, please let me know! I still have full access to these chemists tomorrow, and don’t mind asking if its pertinent to our work.


Thought about experimenting with a heated column?


Is centrifugal partitioning chromatography worth trying?


Heated column no. Heated/warmed solvents, yes . :blush:


what do they recommend for flushing and reusing the magsil column? have you started going through how many times you can do this before it wont regenerate any longer?


There are a lot of 3rd party flash column manufacturers, I’m most interested in cheap disposable silica columns using an isocratic method so you can reuse the solvent easily.

What mobile phase system are you using?


yes this is kinda off topic but still chromatography, supercritical co2 vertical countercurrent chromatography columns design and packing materials of sam


I started initial tests with this today. Flushed columns with methanol. They looked significantly cleaner after a good amount of flushing. We ran a 2nd sample at half the load % used before. I am expecting reduced scavenging capability of the MgO after flushing it, and not reactivating it. We will be doing more research into the re-activation of the florisil and its reduced capabilities after flushes, soon.


Hexane/Heptane and most likely Ethyl Acetate. We may look into cheaper solutions to the Ethyl Acetate soon, but its pretty cheap as is.

Isocratic is great for normal phase pesticide reduction.


Answer is yes, for cannabinoid isolation. Have the $150K for the smaller unit? Or $300k for the larger one? We will be looking into operating costs of that vs reverse phase using c18 columns, soon. That’s after I get the pesticide stuff done.


Yeah I’ve gotten good separation with 5-10% EtOAc. Have you tried ethanol in place of ethyl acetate?


I have not yet. I am interested in doing so, but I don’t have very high hopes as that is a pretty polar/strong solvent.


do you have a cpc too? that does not work for the remediation? So you find reverse phase works for all the pesticides or you still do a normal phase and then also a reverse?


i ran a test where i used acetonitrile as a flush and ran same load through the column and did see slight scavenging decrease but still worked pretty well. it did not do nearly as good as removing pigments though, so i think it still needs more work.


Hold up here… CPC will separate with about 90-95% purity, and it does this through a separation of different compounds/molecules centrifugally. Our pesticides, at times, will have molecular bonds to some cannabinoids. Thus we need to use a different separation method than just centrifugal processes. That is using solid phase extraction, sometimes with activated media that has affinity to bind with our pesticides we are working with. I hope to have a triple-quad MS/MS, for myself :smiley: on site in a few weeks, so I can really start compiling data to release some nice journals on chromatography media affinity towards specific pesticides in our oils. Basically, some medias will remediate some pesticides,and others which are more expensive will strip the oil of ALL pesticides. I just need to get my test results in from some different test trials I have done. I will also be checking solvation effects, before I scale up, as some solvents my have an affinity to aid in removal of some pesticides more than others.

This is ALL in normal phase. No reverse phase yet. If you want to do reverse phase, so you can use ethanol/methanol and water, I can also do that with a different reverse phase media. We aren’t doing that now for extract though. I am banking on a multi-phase chromatographic solution for pesticides in cannabis oil. By Q3, I plan to have most of my work on pesticides finished.

Speaking of pigments, I noticed when using florisil/magsil that some of my first fractions have a grape juice like (lol) purple tint film form on the surface of test tubes… Anyone have any info on if that’s the MgO leeching/passing through? It even occurs on first runs with the column, but it is worse on 2nd runs if I flush methanol in between. I will post a pic in the evening if I remember to snap one of the purple tinted fractions.


I just purchased a flash system to do some R&D with myself. Can I ask what hardware you are using to pack your own flash columns? There’s lots of options out there. I want to be able to pack my own flash cartridges with Florisil so I can fart around and play with some variables.


Our first florisil gradient. We went isocratic after this.


Using hand packed columns for small scale. Medium scale, I am having my handyman make some wood plates to set/fit the columns in, on a laboratory vibrator setup. Plan to dry load the florisil by hand. Biotage recommends this, as we aren’t doing high accuracy compound separations here, just scavenging pesticides. Thats the best info I have! :wink:


CPC will separate pesticides. Cannabinoids and pesticides don’t bond, they may just have an intramolecular affinity. But CPC can easily resolve that.,…


Ummmm, I think you’re wrong there buddy. Got a demo nearly a year ago, and it couldn’t do shit to a fairly basic spiked pesticide panel.