[Chimera]

I use plates designed for acidic cannabinoids, rather than decarbing the material prior to extraction, or worse yet on the plate.

Mobile phase is methanol and water with 1% glacial acetic.

Spot identification by UV, forget fast-blue or vanillin. It's a more expensive initial investment by a few hundred bux, but worth the hassles it saves in the long run.

I'll see if I can find and post some pics.

[sadpanda]

one thing i really like about Fast Blue though is its color differentiation as well... even though the CBD spot is always going to be in that same spot above the THC spot i find it nice to be able to see exactly which color is which - where one stops and the other starts... im guessing you can't really get that with UV, plus i dont think i'd be able to do a flatbed scan of the results?

Would love to see any pics you have anyway, thatd be great thanks!

i was intrigued when you mentioned vanillin alongside Fast Blue so i did some googling there and came across this interesting mention of three different cannabinoid tests:

The Beam test is relatively specific. It gives a purple color with 5% ethanolic KOH, based on the oxidation of CBD, CBG, etc., and their acids to hydroxyquinones. However, THC does not react to the Beam test. Only two plants (Rosemary and Salvia) out of 129 common species tested give a weakly positive reaction. Among some 50 pure vegetable substances such as mono- and sesqui-terpenes, aromatics, etc., only juglone, embelin, and alkyl dioxyquinone develop a color reaction close to that of Cannabis. The reaction is not always dependable; it can be absent if the ethanol is hot.

A modification of the Beam test uses absolute ethanol saturated with gaseous hydrogen chloride. When added to an extract of suspect material, it gives a cherry red color which disappears if water is added. However, the test also gives more or less similar red color reactions with pinene, tobacco, julep, sage, rosemary, and lavender, etc..

The colorimetric test of Duquenois and Moustapha is not so specific as the Beam test, but it is very sensitive. The test reacts to CBN and CBD, but not to THC:

Vanillin (0.4 gr, acetaldehyde (0.06 gr) and 20 ml 95% ethanol is stored in a bottle. Extract the plant material with petroleum ether, then filter it and evaporate the solvent. Add exactly 2 ml of reagent and 2 ml concentrated hydrochloric acid. Stir the mixture; it turns sea-green, then slate gray, followed by indigo within 10 minutes. It turns violet within 30 minutes and becomes more intense.

The Duquenois-Negm hydrogen peroxide/sulfuric acid test is suitable for following the development of the resin and its potency. Macerate cannabis in chloroform or light petroleum ether for several hours. Evaporate 0.2 ml of the extract in a porcelain dish. Add 2 drops 30% hydrogen peroxide and 0.5 ml concentrated sulfuric acid. Rotate the dish gently, and observe the color of the liquid after 5 minutes. A pink color indicates CBD; blood-red color indicates a high concentration of THC. Violet or strong brown indicates THC. CBN produces a green color which quickly turns green-brown.

src: https://www.hempbasics.com/hhusb/hh6thc.htm

[G.O. Joe]

Originally Posted by Chimera

I use plates designed for acidic cannabinoids, rather than decarbing the material prior to extraction, or worse yet on the plate.

Mobile phase is methanol and water with 1% glacial acetic.

Are these C18-type reverse-phase plates?

[sadpanda]

yes i'd too love to hear more about these "plates designed for acidic cannabinoids" please!

[Chimera]

Originally Posted by G.O. Joe

Are these C18-type reverse-phase plates?

Those are the ones, Aluminum backed C18-W Silica, uv254

"Designed for cannabinoid-acids" were not well chosen words, call them suited for the purpose. Either way, they work well.

THCa and CBDa separate out fine, you can play with the ratio of methanol : H20 and length of time in the mobile phase, which provides for better resolution between spots. i will typically just make a 'standard' of known THC and known CBD plants, then blot these for reference points on either side of the plate - unknown samples go in between.. Pics forthcoming.

It'a very suitable method for discriminating between type 1,2 and 3 plants from a CBD segregating generation. Quick and dirty and gets the job done with little prop, no machine time, and minimal processing. I have TLC also for CBDv with colorimetry (both fast blue, & vanillin), but to be honest for those populations I would rather use the GC/HPLC due the sensitivity and quantification. I really just use TLC for screening and narrowing down larger populations as seedlings - no point in growing Bt/Bt plants in CBD breeding programs!

[sadpanda]

wow thats very cool!!!
btw what size TLC plate do you recommend for cannabinoids?
[update] it seems all the commercial kits use 5cm x 10cm plates

[sadpanda]

Specifically for testing cannabinoids using TLC...
Q1. Which solvent(s) are recommended for the extraction (ie. bud/resin/oil/etc -> solution)?
Q2. Which solvent(s) are recommended for the mobile eluent phase to carry the solution up by capillary action?

It seems there's actually quite a lot of options, which is good in that it makes more options available in a world where getting some chems can be tricky, but also makes it initially more complicated for newbs like me who don't really know the underlying chemistry too well!

Anyway i put together a list of what some have used/recommended (specifically for cannabinoid testing by Thin Layer Chromatography), just scratching the surface, in no particular order:
_____

https://www.sirchie.com/thin-layer-ch...h-6-tests.html
Extract Solvent: Hydrocarbons C>=5, C5-6-rich (petroleum ether).
Mobile Eluent: 6:4 chloroform : Hydrocarbons C>=5, C5-6-rich (petroleum ether).
(This is a LEO-only kit, i don't know if solvents are chosen for being the most mobile/field-use friendly, or if simply because they produce best results, or both, or...)

https://www.alchimiaweb.com/blogen/m...noid-analysis/
Extract Solvent: hexane
Mobile Eluent: chloroform
(Shows it can be nice and easy, and the photos of the result still look good, but i get the feeling the separation may not be quite as good as with the two-part eluents?)

https://www.medicinalgenomics.com/wp-...f-cannabis.pdf
https://www.researchgate.net/publica...s_TLC_AMD_OPLC
All the standard solutions were prepared in 0.5mg/1mL in methanol.
Cannabis resin (0.1g) extracted by shaking for 20 min with 10mL of hexane.
Hemp sample (0.5g) was extracted for 10 min with 20 mL of hexane.
The filtrate was evaporated to dryness and the residue dissolved in 1mL of toluene.
For Classical TLC and TLC-MAT, the eluent used was 4:1 hexane : diethyl ether.
... it also goes on to say this interesting comparison ...
In the literature, the eluents which are mostly used are:
eluent A: isooctane-ethyl acetate-acetic acid 30:10:1 v/v;
eluent B: petroleum ether-diethyl ether 90:10;
eluent C: acetone-methylene chloride-diisopropyl ether-hexane 1:1:3:20 v/v;
eluent D: toluene-chloroform-methanol 100:10:1 v/v;
eluent E: hexane-dioxane 90:10 v/v double migration;
eluent F: hexane-diethyl ether 80:20.
The eluents A and B result in a clean separation between ∆9-THC and CBN, but not between ∆9-THC and CBD.
With eluent C, the main Cannabinoids are separated but the spots are stretched.
The best results were obtained with eluent F, hexane-diethyl ether 80:20 v/v which allowed a clean separation of ∆8-THC, ∆9-THC, CBN and CBD.
Different eluents were tested: isooctane, heptane, hexane, pentane with diethyl ether with a ratio of 90-10 v/v. The comparison between these four alkanes showed that the separation capability decreases when the carbon-bearing chain lengthens.
(so at this stage i think this is what i'll personally try to get, and its handy that the hexane can be used as both extract + mobile, so only the two chems needed, yet still with a two-part mobile phase for excellent separation!)

https://www.icmag.com/ic/showpost.ph...6&postcount=19
Extract Solvent: petroleum ether
Mobile Eluent: 4:1 hexane : ether

https://www.icmag.com/ic/showpost.ph...1&postcount=62
UNODC document: 4:1 petroleum ether : diethyl ether
Perhaps ethyl acetate and many other things can substitute for the diethyl ether polar part.
A nonflammable option is chloroform with just a little bit of methanol.
1:1 hexane : methylene chloride.

https://www.botanicalauthentication.o...ce_and_leaf%29 (Uni Mississippi)
Mobile Eluent: 0.1% glacial acetic acid in a mixture of methanol and water (75:25)
Extract Solvent: 100mg powdered plant material in 10ml dichloromethane, evaporated, dissolved in 10ml methanol.

https://www.icmag.com/ic/showpost.ph...4&postcount=63
Mobile Eluent: methanol and water with 1% glacial acetic. (*with TLC plates designed for acidic cannabinoids)

https://www.patentstorm.us/applicatio.../fulltext.html
Chromatography on silica gel (0.035-0.070 mm, chromatography with a mobile phase mixture of 1% by weight ethyl acetate in petroleum ether) resulted in a cannabinoid fraction which was detected by TLC [silica gel 60 F254 (HPTLC pretreated plate), hexane/diethyl ether 8:2; detection: 125 mg of fast blue B salt in 30 ml of 1 N sodium hydroxide solution, dist. water ad 300 ml, evaluation under daylight].

https://www.sciencedirect.com/science...21967301953476
Extract Solvent: light petroleum (BP 40-60°)
Mobile Eluent: two systems
1) 15:1 chloroform (ethanol-free)-1 : 1-dichloroethane
2) 19:1 xylene (mixed isomers)-1 : 4,dioxan

https://scholarlycommons.law.northwes...2&context=jclc
Extract Solvent: .3ml (6 drops) petroleum ether for a few minutes
Mobile Eluent: toluene, "however benzene or xylene could probably be used with similar results"

https://www.unodc.org/unodc/en/data-...4_page011.html
Toluene for elution in one direction (first front) and 9:1 hexane : dioxane for elution in the perpendicular direction (second front).

https://montanabiotech.com/2011/05/2...ntana-biotech/
Mobile Eluent: 15:10 chloroform (ethanol-free) : 1,1-dichloroethane

https://www.google.com/patents/US20070077660
Good results are obtained with a developing solvent with at least 25 vol. % chloroform and at least 25 vol. % 1,2-dichloro ethane.
Extraction solvent comprises at least 50 vol. % chloroform, relative to the total volume of the extraction solvent.

https://www.thctalk.com/cannabis-foru...post1069722795
Extract Solvent: hexane
Mobile Eluent: 4:1 hexane : diethyl ether

https://www.realhemp.com/wp-content/...annabaceae.pdf
either a polar (ethyl acetate-methanol-aqueous 2% acetic acid; 67:7:1)
or more non-polar (toluene-ethyl acetate-formic acid; 17:10:1) solvent.

https://ww.asianforensic.net/document...sue7_Final.pdf
Thin layer chromatography (TLC) plates should be silica gel or equivalent and sufficient to resolve the three major cannabinoids. Sample A was spotted on the TLC plate with the cannabinoid standards. Mobile phase was petroleum ether:ether (80:20). The visualisation spray used in this method was Fast Blue BB salt. Approximately 50 mg of fast blue BB was dissolved in 20 mL of 0.1 N sodium hydroxide. This solution was freshly prepared. Results obtained from this analysis showed that the three cannabinoids migrated and developed in the following order;
• Top spot – Cannadiol (CBD)-orange
• Middle spot – Tetrahydrocannabinol (THC)-red
• Lower spot – Cannabinol (CBN)-purple

[SkyHighLer]

Do you really need optimum? Some of those solvents are of the type usually reserved for real chemists... diethyl ether is not something I keep around the house.

Both diethyl (ethyl) ether, toluene, and acetone are on the DEA precursor watch list, and if the only source of chloroform at eBay is outside the country, something's up, and I would look into why before attempting to purchase it.

"List II chemicals

These chemicals are designated as those that are used in the manufacture of the controlled substances.

Acetic anhydride
Acetone
Benzyl chloride
Ethyl ether
Potassium permanganate
2-Butanone (or Methyl Ethyl Ketone or MEK)
Toluene
Hydrochloric acid (including anhydrous Hydrogen chloride)
Sulfuric acid
Methyl isobutyl ketone (MIBK)
Sodium permanganate"

https://en.wikipedia.org/wiki/DEA_li...t_II_chemicals

[G.O. Joe]

AA and BnCl are really the only suspicious chemicals for domestic delivery on that list. The truth is ether is not a big deal to work with, separate from starting fluid, whatever.

[sadpanda]

is "Fast Blue BB salt" just zinc chloride? could i just buy 1gm zinc chloride salt?
[edit] oops guess not ... "(Fast Blue BB) salt is a zinc chloride complex of diazotized 5-amino-2-benzoyl-amino-1,4-diethoxy-benzene"

[edit] lol, actually Joe when i asked that question you probably should've stopped helping and told me to go find another hobby. I think i was having a long week...