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Old 12-06-2009, 06:47 AM #21
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BTW,

You don't need all the materials I listed, like pipett, some jars, eppendorfs, etc. I made the list a bit bigger than the bare minimum. But, if you have the money my previous list can allow you to process more samples simultaneously and give you greater flexibility.

Here is what I think might be bare minimum:

Silica plates

Glass/pyrex jars a few sizes up to 1L.

Tweezers

Spatula (5mg)

Microscale

Many disposable capillary micropipett (3ul)

Filter paper or blotting paper or paper towel

5ml vials

50 ml test tube

Motor and pestal
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Old 12-06-2009, 07:19 AM #22
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One last thought.

I will upload my digital mini-library on TLC, HPLC and GC; all on the topic of cannabis. Mostly TLC but the best manuals by the UN and NATO also have great directions for testing all kinds of drugs with TLC, GC, HPLC, etc. I can probably upload 5-10 full text journal article plus manuals from the DEA, UN and NATO.

I think people will learn a lot from them.

I will also post a how to for a DIY "fume hood", a must have for indoor solvent work!

Lastly, here is a great chemistry resource, a chemistry link-o-rama, people WILL learn a lot for this great (underground) chemistry page! Or they are already chemists:
https://www.erowid.org/archive/rhodiu...try/index.html
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Old 12-06-2009, 03:04 PM #23
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Rather than develop the plates with chemicals why not use silica that has the fluorescent indicator in it? Then all you need to characterize the spots is a UV light box. Less dicking around. Also, TLC thickness is notoriously inconsistent when you make the plates yourself. I'd use chromatography paper instead, much more reproducible results.

That Erowid link-o-rama needs a bit of caution when reading. For example, the THC total synthesis given is a real boner, a better one (less steps, most of the starting products unwatched) exists.

I'm very interested in viewing the articles in your digital mini-library, once they are made available.
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Old 12-06-2009, 04:45 PM #24
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Hey

Using Rf vales is harder and a lot less accurate than scanning spot densities.

More expensive too. Ill try to upload the papers tomorrow.

Nobody making plates themselves. I noted that is the biggest cause of error, the plates. Chromatography paper is less accurate, can't get semi-quantitated results AFAIK. Not much dicking around, esp when the results are analytically valid as HPLC...



HTH
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Old 12-06-2009, 07:19 PM #25
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Making or ordering standards:

As I mentioned before, one can use TLC (with effort) to make pure standards of THC (for example). That is great because it enables one to use true quantitated results with TLC on the cheap! See this thread:
www.chemicalforums.com/index.php?topic=10949.0

Although, if making ones own standard than using HPLC to create standards is generally much preferred. But HPLC are expensive. All I need to do is figure out what solvent to use to remove the silica, and maybe a second purification step, but its possible, tho not simple. Once one has their standard they need to test it to insure its purity, two tests are ideal.
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Old 12-06-2009, 09:38 PM #26
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Use a fume hood or other ventilation for indoor work

It is important to use a fume hood or work in a well ventilated area when using n-butane or other volatile solvents and chemicals.

Uses:
  • A fume hood would be used for the extraction apparatus to remove gas.

  • Fume hood is used for toxic volatile solvents like torlene (sp?) which is common in TLC.

  • A water aspirator would be used for boiling off the ethanol to remove gas (and lower pressure).


Its not hard to build a portable fume hood using plexiglass and a little math.

The fume hood will have to be large enough so the extraction apparatus can fit inside.

I will do a pictorial how to when I build one, but here's the dirty:

Build a three sided box, say 3'x2'x2' (LxWxH), although a truncated triangular footprint might provide better air velocity[1]. Attach a removable 'front' piece of plexiglass with an opening of around 2 feet (enough room to comfortably work). Build an upward sloping 'roof' (like a house's roof). At the center of the roof attach a squall cage fan or in-line fan which can provide a "face velocity" of 90-100 ft/min. If one can't reach a minimum of 80 ft/min than decrease or increase the size of the opening accordingly. Attach a 4" plastic drier hose to the fan and vent it outside.

That's it. Now when extracting with n-butane do so within the fume hood.

SEE:
"Design for a Miniature Portable Fume Hood"
By: R.A. Bailey & S.C. Wait, Jr. J. Chem. Educ. 76(2), 228-229 (1999)

https://www.erowid.org/archive/rhodiu...fume.hood.html
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Old 12-08-2009, 05:36 AM #27
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Hmmm,

Well after some thought and discussion with some chemist friends I am pretty convinced one can not use TLC to detect butane (bp is too low). I shortly considered using a large cooler kept cold for butane TLC, but that seems like a non-starter.

I am still hoping to find some method for testing at home, but it looks like GC is one of the few options. Thus, I will test my solvent-free extract to see if it's truly solvent free (at least totally free from butane). If my new method I'm working on turns out as well as it should I plan on writing a very detailed PDF paper on the 'how-to'. Then if one follows my methods to the letter they could be reasonably sure their extract is solvent free too.
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Old 12-08-2009, 11:16 PM #28
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Wrong forum. Post deleted.
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Old 12-09-2009, 07:12 PM #29
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As promised,

Here is a list of journal articles and manuals from my collection I included in the file "Testing.zip".* I encrypted the folder with the password (not incl. quotes): "TLCrocks"
https://www.filesavr.com/testing_1

TLC:

  • "Analysis of Selected Pharmaceuticals by Quantitative TLC"

  • "Separation and Identification of the Consitiuents of Hashish by TLC in Forensic Analysis"

  • "Evaluation of quantitative TLC using Staining Reagents" --> paper about and review of "JustTLC"

  • "Silica-Gel TLC Protocols"

  • "TLC Test Protocol" --> GREAT manuel, excellent pics and explanations




GC:

  • "Gas Chromatographic Determination of Tetrahydrocannabinol in Cannabis"




Multi tests - TLC, GC, HPLC:

  • "The Analysis of Controlled Substances"

  • "Identificiation and Determination fo Cannabinoids"

  • "Simultaneous Seperation and Identification of Hashish Constituents by Coupled HPLC-MS"

  • "Reccommended Methods for Testing Cannabis"* ---> Untied Nations manuel from 1987 (info still valid)

  • "Detection of Cannabis in samples of different sources"* ---> The TLC method on page 6 is what I plan to use.* I might replace hexane.
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Old 12-10-2009, 03:12 AM #30
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A note about using TLC to create a standard from silica stationary phase:

"Silica gel can be dissolved by solvents containing more than 10% MeOH."

See the following paper found in the folder "TLC" in the file "Testing.zip" I uploaded:

"Silica-Gel TLC Protocols"
Author(s): Unknown
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