Hi everybody. SWIMs been scratching his head and reading lots. He's just done his third extraction (first time on some MHRB) and is getting a very poor yield. On 1.5kg of bark, powdered in a blender he got about 3g total (0.2%). He's read of other people sometimes exceeding 2%. He didn't follow a tek exactly but feels he did things in a way which should result in a higher yield than this.

-Powdered bark in a blender.
-Boiled bark 4 seperate times in a pH 4 vinegar/distilled water solution for about an hour each time (3 hours on the last boil)
-Reduced the acidic solution to about 2 liters (a bit low but didn't think it would impact yield severely)
-Transferred filtered acid boils to 2 large jars.
-Performed a defat step on one jar, but not the other, using about a litre of ronsonol lighter fluid.
-Basified to pH13
-Pulled with heptane @ 70°C until nothing preceipitated when put in the freezer @ verycold°C
-Added pure NaCl to the basic solution until saturation
-performed one more heptane pull with minimal results.
-After pulls, product was recrystallized with heptane yielding roughly 3g of slightly off white powder.
-Including yellow goo left over from recrystallizations yield may approach 4g.

He is wondering why his yield is so low for the amount of bark he used and what he can do in the future to make it better. Is it likely just low quality bark? He doesnt see where he could have gone so wrong in the extraction as to lose a potential of 90% of the alkaloids.

SWIM has done 2 extractions before on acatia confusia. He recalls getting a decent yield with each pull even after the 12th pull, and a rough estimate of 1.5%.

In the case of this most recent extraction on MHRB he only did 3-4 pulls before they stopped yielding anything.

Please help SWIM improve his tek!

Your process looks very normal, and you should have had better results than that. (Good notes btw) Did you run into an emulsion? The only thing you didn't note is how big your heptane pulls were. Was the heptane still cloudy after chilling? I doubt this is it though. Are you positive the PH was high enough? You can always add a little bit more to make sure. I don't even measure my lye - just add until the color/consistency is right, and add a bit more for good measure. If I question the quantity that I'm getting from the pulls, I always add a bit more lye and try again. You don't have to follow teks perfectly to get great yields. It looks like you're pulling from multiple teks, and you've taken time to understand the science. That's what really matters. I bet it is the quality of your bark. Perhaps it was regular bark instead of good quality inner root bark.

What is the technique of your pulls? How much solvent, how do you mix it, how long for?
Heptane is very selective and is not dissolving dmt as good as other solvents. I personally wouldn't it use for initial extraction. In fact, I wouldn't use even naptha and rather use toluene. But this is just my personal opinion, I don't like doing many and many pulls at that stage. With toluene only two pulls are required to get almost everything out of the bark.

Nonetheless, the quality of the bark is the most likely suspect here.

Thanks guys. That puts my mind a bit at ease. I pulled from the roughly 1000ml solutions wiht about 500ml of heptane (I only manage for pull about 400ml ml off for each freeze precipitation.) I reuse the freeze preciped heptane for the next pulls. It is always kinda yellow, but not cloudy after the freezer. I used the same heptane for both jars, saving the fresh stuff for recrystallizations. I pull by shaking the jar a few times very well letting it seperate inbetween as the jar is headted in a 60-70°c bath. After I waa done pulling everything the heptane would grab I would add salt and more NaOH, and get onpy a little bit more from that usually. I ran some DCM through it after all of this, just to make sure everything had been gotten.

Just trying to do everything that seems logical to get all of the goodies out.
Am I allowed topst my source to see jf you guys might have jad simmilar resutls with their bark?

I didn't run into any emulsion issues. I shook the heck out of it, but it always seperated with 20min max.

Your technique sounds good. So it seems your bark is not good.

No, discussion about sourcing is not allowed here.