doubts about purification

[Doclad]

Greetings.


I'll be quick.


1. I bought 3-mmc. I analyzed it (GC/MS), the result was 63% purity.

2. I washed it with anhydrous acetone. I analyzed it again (GC/MS), the result was 65%.

3. I wanted to go further. I made an A/B extraction with HCl to make sure to obtain a high purity percentage. I sent it back to analyze (GC / MS), the result was 65%.

I have lost half of my product trying to purify a substance that shows the same percentage of purity after an A/B extraction.

What can be happening here?


DocLad

 

[adder]

Well, obviously the impurity or impurities are weakly basic thus go into acidic aq. solution along with 3-MMC and go into organic solvent when aq. layer is basified. Have you got any information about the identity of other compounds or just a rough number of 65% back? If you only have this 65% figure, then it may be anything, it could be some other cathinone, pyrrolidinophenone or amphetamine. A common impurity for cathinones are also corresponding isocathinones, no idea why that is the case as their presence would likely have to involve the formation of the imine from the desired cathinone product and excess alkylamine and then tautomerization to enamine (actually "endiamine") which at least partially then hydrolyzes into isocathinone. Quite weird, though I see no other way an isocathinone would be formed as a side product.

 

[Doclad]

Well, obviously the impurity or impurities are weakly basic thus go into acidic aq. solution along with 3-MMC and go into organic solvent when aq. layer is basified. Have you got any information about the identity of other compounds or just a rough number of 65% back? If you only have this 65% figure, then it may be anything, it could be some other cathinone, pyrrolidinophenone or amphetamine. A common impurity for cathinones are also corresponding isocathinones, no idea why that is the case as their presence would likely have to involve the formation of the imine from the desired cathinone product and excess alkylamine and then tautomerization to enamine (actually "endiamine") which at least partially then hydrolyzes into isocathinone. Quite weird, though I see no other way an isocathinone would be formed as a side product.

Thanks for the reply. These impurities that you mentioned are active in some way? what is the toxicity profile?


DocLad

 

[Hodor]

I was going to say pretty much the same thing that adder posted: not all impurities are created equal. If they are salts of organic amines - which would apply to synthesis byproducts as well as other RC stims added as active cuts - you're not going to be able to separate them via a simple acid/base extraction.

Thanks for the reply. These impurities that you mentioned are active in some way? what is the toxicity profile?

We basically have little to no info on isocathinones... if they are indeed active, they are probably only a fraction of the potency of the parent drug.
To be honest, we barely have any information on the toxicity of the cathinones (or other RC stims) that have actually proven moderately popular, not to mention the fact that we still don't know *which* of those are in your product.

 

[Doclad]

Unfortunately the results of the analysis (GC / MS) provided by EC do not give any information about the possible contaminants of the sample, they only offer the purity percentage.


DocLad

 

[vecktor]

Unfortunately the results of the analysis (GC / MS) provided by EC do not give any information about the possible contaminants of the sample, they only offer the purity percentage.


DocLad

Given that EC haven't got a reference samples and no calibration curves for 3MMC any numbers for purity are wild guesses, as are a lot of their identifications.
What is this 65%, The most likely is that the 65% is that the 3mmc peak is 65% of the total ion count TIC and that is pretty meaningless because the impurities could give a very different response in the MS and it is also conceivable a 100% pure material could breakdown in the GC to give a mixture. EC wouldn't have bothered to check.
The other possibility is that the 65% number is the % hit match against the reference spectrum in the database, in which case it is alwyas going to be 65% +/- irrespective of what purity it is.
Acid base is pretty much a waste of time because the manufacturer would in effect have already done that. it is likely that the material was made by precipitation of a hydrocloride from a non polar so any acidic substances and neutral substance are going to remain in the solvent, solids are filtered and these are salts of basic materials.
Recrystalisation of the salt from ethanol or isopropanol would be more effective than acid base.
Overall the best purification strategy for 3MMC is to throw it down the toilet, you will feel much purer then.

 

[Doclad]

Given that EC haven't got a reference samples and no calibration curves for 3MMC any numbers for purity are wild guesses, as are a lot of their identifications.
What is this 65%, The most likely is that the 65% is that the 3mmc peak is 65% of the total ion count TIC and that is pretty meaningless because the impurities could give a very different response in the MS and it is also conceivable a 100% pure material could breakdown in the GC to give a mixture. EC wouldn't have bothered to check.
The other possibility is that the 65% number is the % hit match against the reference spectrum in the database, in which case it is alwyas going to be 65% +/- irrespective of what purity it is.
Acid base is pretty much a waste of time because the manufacturer would in effect have already done that. it is likely that the material was made by precipitation of a hydrocloride from a non polar so any acidic substances and neutral substance are going to remain in the solvent, solids are filtered and these are salts of basic materials.
Recrystalisation of the salt from ethanol or isopropanol would be more effective than acid base.
Overall the best purification strategy for 3MMC is to throw it down the toilet, you will feel much purer then.

Today I have spoken with EC and I have told him what he has written here.
I have been told that the percentage has been calculated with UV instead of (GC / MS).

What exactly does this mean? Is it a reliable test?


DocLad

 

[vecktor]

Today I have spoken with EC and I have told him what he has written here.
I have been told that the percentage has been calculated with UV instead of (GC / MS).

What exactly does this mean? Is it a reliable test?


DocLad

depends what is meant by calculated by UV
if they have a reference of known purity, and used it to generate a calibration curve on their HPLC with their column and they ran the sample through the same HPLC and the UV refers to UV detection of the peaks from HPLC then it is reasonably reliable +/- 2% is usual. If they didn't run calibration samples and have a calibration curve then the results are very unreliable.
if they just dissolved it in solvent then measured the UV absorbance without separating the components then it is much less reliable,
In my experience EC data is not very scientifically sound, it is there to discover what is out there and provide that information to the authorities and very occasionally prevent a complete disaster.


.

 

[Doclad]

Thank's for your answers.


DocLad