I am wondering if there is a more affordable option for cannabis sampling to the 1600 Mini G Grinder. I am ideally looking to avoid spending 17k CAD on a grinder if I dont have to. We are currently using a mortar and pestle however the HPLC specialist training us on the equipment said that it is not adequate.
Any recommendations are greatly appreciated.
Freeze the flower in a -40 fridge, remove and crush between fingers. The entire flower should crumble to dust.
We have a harvest right on-site. I understand not the same as freezing to -40 but could achieve same end result?
you can use a $20 food processor.
in regards to sample prep the purpose of the grinder is to homogenize your sample. not sure how a food processor wouldnt work.
I use one of those little bullet blenders.
Iâd have to say thatâs overkill brother. I just use a regular grinder, ensure itâs as fine as itâll go, and run with it!
Canât imagine any issues with doing it that way. The third party lab in town will use N2 (l) to speed things up too. The cold helps to âfreeze it in timeâ.
If youâre still not convinced, prep samples with the fancy grinder and prep w/o. See what results come back!
Yes that will work fine.
I think the issue with all the grinder options is that you would have to clean the grinder everytime to ensure you dont have cross contamination between samples. Imagine if you ground a sour diesel sample in a regular weed grinder and then had to do a hemp sample? The results would be all compromised
This?
https://www.spexsampleprep.com/minig
What is the goal of your analyses?
If youâre just doing in house potency, there is no need to get at the cytoplasm. Our target is not in there.
If youâre looking to do in house or third party pesticide testing, and you want to know that youâre doing your due diligence, the opening every damn cell with a tissue homogenizer such as this is appropriate imo.
In the analytical chemistry world, one has to validate against other methodsâŚI donât currently have an analytical lab director I can text with that question, but Iâd bet money he would agree that the gold standard against which the mini g is ultimately compared to is liq N2 and a mortar & pestle.
Thatâs how I was taught to get the DNA/RNA/protein I was after as a youngster. Turned out there were faster methods 
Why exactly does your trainer object to? What are their qualifications? Experience?
Correct, you need to decide how you plan to clean between uses. It is 100% possible, many accredited labs are using reusable vessels with success. They do studies to demonstrate their methods prevent cross contamination.
We have an Autoclave in the lab for sanitizing our equipment between uses. I also plan on having multiple grinding containers.
We are just doing in-house potency testing to help with pheno hunts and business decisions regarding strains. Anything that is reported has to go through 3rd party lab anyway.
Yea for in-house use id say just freeze your samples and crush them up on a separate weigh boats. Its cheap and does a pretty darn good job. One issue i find with the grinding flower samples particularly kiefy high potency stuff is that so much of the kief clings to the surfaces of the grinder, weigh boat, container etc. I find that sampling a ground material like this may be more compromised than if you were to take a few whole flower samples and average their results.
Whats everyoneâs process after they grind. Essentially what are you doing to extract the ground up leaves?
We mostly only test concentrates but when we test flower we dont have the most time efficient methods. Currently we soak ground up leaves in ethanol then ultra sonic and then buchner filter the solution, then we re extract the same leaves 2 more times in the ultra sonic and then filter it two more times.
I was thinking about getting a little benchtop centrifuge to speed this process up, but wanted to see what others are doing?
Also as a side note you should retest your âspentâ flower that you extracted to ensure you got all the cannabinoids out.
How long do you sonicate for? Plant material in ethanol sonicated for 15+ mins should be more than enough to get a full extraction. To save some time get yourself some syringe filters and filter the solution right into an autosample vial and eliminate the need for the buchner funnel. Have you tested your solution between soaks? Does the concentration of cannabinoids go up in each subsequent soak?
in this instance, your âexpertâ is incorrect, and I would wager they have not performed potency testing on cannabis in any real world capacity.
youâre not concerned with opening the cells up, just making sure that the sample you take is actually representative of the biomass youâre sampling.
the larger the sample you homogenize, the more accurate your tests are going to be.
ask them what sort of the variance in flower potency from flower to flower is expected. Iâve taken a single branch, and tested flowers from tip to toe. potency ranged from >20% to <10%.
using a $17k homogenizer to grind 1gm samples is ludicrous when faced with the biology of the problem.
Great, appreciate your reccomendation.
So to summarize, so long as the sampling process is good - the mortar and pestle + freeze dried samples should do the trick in our situation?
We sonicate for 1 hour, and yes we also use hydrophobic syringe filters before we inject anything into our hplc. The reason for the buchner filter in our process is so we can reextract the spent biomass to remove the remaining cannabinoids.
Yes we have tested in between each step and were not getting full extraction which is why we are doing it 3 times.
does the % left behind change?
if you always get 75% extraction efficiency, do you need to achieve 100% to know the potency?
