[zif]

^ Are the cannabis sex chromosomes as easily distinguished as human sex chromosomes? Any reference images?

[Ringodoggie]

Apparently so. I saw a company offering sexing if you send them a small piece of a leaf. They said they used simple DNA viewing so I read up on it a little.

I didn't get a ton of details but apparently it is something that is pretty common and not outside the scope of a home user.

Just like home TLC or any other test. There's an initial setup fee and then there's a learning curve.

I am playing with the color testing for THC and CBD right now but sexing via DNA is on my list.

I don't want to drag this thread off topic. Google "y chromosome in cannabis plants" and you'll find a ton of info.

[Chimera]

Originally Posted by zif

^ Are the cannabis sex chromosomes as easily distinguished as human sex chromosomes? Any reference images?

Not by eye, no... in fact they are quite difficult to distinguish by eye alone.

They use a technique called PCR looking for specific genetic sequences found only in male plants.

HTH,
-Chimera

[dybert]

Originally Posted by PhenoMenal

p0opstlnksal0t,
my advice is don't bother trying to get % from home TLC, there are too many variables that all need to be exactly 100% just to get semi-accurate readings. TLC is a qualitative test, not quantitative. You really need to send it to a lab if you want %'s you can rely on.

It's still a beautiful tool for revealing both the EXISTENCE and RATIO and APPROXIMATE QUANTITY and overall FINGERPRINT of cannabinoids though!!!♥ just not accurate %.

You mentioned selling it as a service, but I feel you would be doing a disservice to your clients by using TLC to provide %'s because you could be off by as much as 5-10%, which is a huge error margin considering strains top out at ~30% THC. If people are willing to pay for such a test they generally want accurate results, and TLC's margin of error simply cannot accommodate that.

For example, in the AlphaCat image you posted for example, look at the 12% and 17% blobs:
View Image
... almost identical to the naked eye yet 5% difference. I would encourage you to provide a scan of the plates to clients, rather than %'s, because it really is afterall a VISUAL test (hence the need for the special Blue B/BB dye!), and one that doesn't provide concrete numbers.


sweet!!! where!?

For the most part you are right, but I used to run an analytical company based on Arno Hazekamp's quantitative TLC methods for cannabis. I was blind tested against an HPLC by Halent Labs and Steep Hill labs and was found to be within .5% accuracy.

The best solvent for this is hands down chloroform (which is dangerous and hard to get). I have tried probably every solvent combination trying to get better separation, and have not succeeded.

If I get ambitious maybe I'll bring my results server online and let you guys poke around... I tested all of the High Times Cannabis Cup samples in Amsterdam in 2012. So I know for a fact that the Greenhouse Seeds sponsored winner (8% THC) was bullshit lol. Its not based on any sort of credible information other than how much who paid.

[PhenoMenal]

Originally Posted by dybert

The best solvent for this is hands down chloroform (which is dangerous and hard to get).I have tried probably every solvent combination trying to get better separation, and have not succeeded.

If possible it would be great if you could you please list the other solvent combo's you've tried!
(out of curiosity I couldn't help but try a few others myself) ...



btw u should not have problems acquiring chloroform, just call your nearest lab supply store "do you have a small quantity of chloroform suitable for Thin Layer Chromatography?" (there are different grades, purity etc). They have small 250mL, 500mL etc bottles. I don't think it's a "controlled substance" per se, not sure tho, and obviously each country has its own laws. Looks like it's easy to get just from ebay etc too.

btw, any idea why chloroform gives that "curved jar" effect on the TLC plate? (by comparison the 4-to-1 hexane - diethyl ether results in a 'flat' (normal/expected) effect. This remains a mystery to me

[p0opstlnksal0t]

Originally Posted by dybert

For the most part you are right, but I used to run an analytical company based on Arno Hazekamp's quantitative TLC methods for cannabis. I was blind tested against an HPLC by Halent Labs and Steep Hill labs and was found to be within .5% accuracy.

What is the secret to getting within 1-2% accurate quantitative results? I will look into Arno hazekamp. I was hoping to build some software where I could scan in my plates and the software will measure the spots much more accurately than my eyes. Unless there is already software out that for this method?

[OXOSSI]

Here are som things to try
1- Your sample is to large. Diminish
2-Hex-EtOH(10%)
3-Ether (EtOH 5%)
4 - Hexane-Acetone 4-1
5 Ether Hexane 1-1
6 - Acetone-Ether

Let me know what resolution you get
Diclhoromethane substitutes well for chloroform
last pick looks the best, work with that altering the ratio of solvents (reduce ether, try 7 to 1) and most importantly, sample loading should be smaller for better resoultion. Optimal plate should have an Rf of no more than 0.5 so that you could run it a fw times.

[PhenoMenal]

Originally Posted by p0opstlnksal0t

I was hoping to build some software where I could scan in my plates and the software will measure the spots much more accurately than my eyes. Unless there is already software out that for this method?

there is JustTLC etc, but there's more to it though than just converting an image to grayscale and checking the 0-255 value of each pixel within the blob ... Fast Blue B/BB for example dyes specific chems different colors (THC is red while CBD is orange while CBG is yellow-orange etc etc etc), so it would make it very tricky to compare the % of each chem in a single analysis, although comparison of the same chemical would be more viable (eg. CBG on one plate and CBG on another), but then you're also having to deal with two different sample applications which are almost certainly at least slightly different sizes if not done under strictest lab conditions

[PhenoMenal]

Originally Posted by OXOSSI

Here are som things to try
1- Your sample is to large. Diminish

Please expand your commentary on this! I only use 2 to 3 microdots from the pipette on each TLC lane

and most importantly, sample loading should be smaller for better resoultion

ie. so i should be using 1-2 dots instead of 2-3? or..?

work with that altering the ratio of solvents (reduce ether, try 7 to 1)

I haven't experimented with hexane : diethyl ether ratios yet

But something weird happened the last time i used it, which I have no explanation for what might've happened... which i consider a MASSIVE FAIL:


The eluent was hexane : diethyl ether @ 4:1 (which i had used a dozen or so times before this first fail), but for some reason liftoff failed!!! FWIW the other plate which i did with chloroform worked normally

I wonder if i was too complacent/slack in not being strict enough about the hexane and diethyl ether ratio ???

[OXOSSI]

Then repeat the TLC 2-3 times. It moved slightly, add a drop of EthOH to increase polarity of the mobile phase. All trial and error.
Take the plate out, let it dry and run it again. Add less volume of product or dilute it.

Here is a pick of decent looking plate

https://www.flash-purification.com/ho...hromatography/