Extracting theobromine from Cocoa

Thanks for the tip, Silviu. SDS doesn't seem to remove enough protein deposits from the sample cells, however. Maybe the proteins adsorb more tightly to pure silica windows than glass or impure silica, or else the small spaces between cell windows prevents cavitation in the ultrasonic bath. But perchloric acid works well in that case.

mrkhrdr@gmail.com

Dichromate won't leach into anything (in my experience) if, after thorough rinse, it's followed by a long soak in alcohol. Any traces of Cr(VI) will be reduced to Cr(III) by the alcohol. TBH I didn't use the sulfochromic mix all that often. SDS usually takes care of anything except for the most stubborn residues.

Silviu T

In a biochemistry lab, it's risky to clean glassware with acid-dichromate. Dichromate in some form is believed to leach into reagents subsequently used in the same glassware. This particularly applies to those pipette washers that include a long soak in an aggressive cleaning solution before rinsing. Sometimes, protein deposits accumulate on the windows of spectroscopy cuvettes and must be removed aggressively. The first attempt is usually sonication of detergent solutions. If that fails, the cuvettes are washed/sonicated with warm perchloric acid. BTW, don't attempt to heat perchloric acid in a microwave oven, esp. when contained in expensive glassware! I won't re-tell the embarrassing incident that taught me that lesson.

mrkhrdr@gmail.com

When I was doing research my go-to cleaning agent was the sulfo-chromic mix. Sulfuric acid and potassium dichromate. It's even more effective than the piranha solution. Creates a bit more waste though and for that it's generally used in larger institutions only.

Silviu T

Thanks, I am glad you enjoyed!

Nile Red

My funnel looked cleaner than when I bought it!

Nile Red

I am now really ashamed at myself for never noticing that thiobromine _clearly_ doesn't contain any bromine, and it would make absolutely no sense that it ever would. Great idea for a topic, btw!

Paul Grodt

Thanks, Silviu. I always cussed those stains, figuring that either I put up with it or toss the glassware. Actually, what I usually did in these cases is doing neither, letting them sit around the lab uselessly...

mrkhrdr@gmail.com

It's a corrosive mix of hydrogen peroxide and sulfuric acid used to clean glassware. It's especially effective on stubborn organic residues. <a href="https://en.wikipedia.org/wiki/Piranha_solution" rel="nofollow noopener" target="_blank">https://en.wikipedia.org/wiki/Piranha_solution</a>

Silviu T

Nice. But what do mean by "Hot Piranha" ?

mrkhrdr@gmail.com

Seriously. It'd be cool to be able to go both ways. It's a lot easier to get pure Caffeine in the US than pure Theobromine.

Roger Lee

Thx for asking that Jordan Blackman. I was thinking that was well. Cheers

It is tough to do because the cocoa is so fine. It wouldn't drain. I didnt have any celite to mix it with, Also, it's mostly because I used a soxhlet to extrat piperine from black pepper. I didnt want to cover it twice . It would have been interesting to compare the results though.

Nile Red

That is very true. Demethylations tend to be more interesting

Nile Red

Should've used a soxhlet! ^^

Gabriel J.

why not both!

Second that.

Silviu T

You can get cocoa nibs at health food stores - those are roasted and broken-up cocoa beans, and generally average 5mm or more. Of course, there are 2 downsides for using those: the larger size means less surface thus slower extraction, plus all of the cocoa butter is still there unlike cocoa powder.

Silviu T

Nice. As a follow-up video, I'd be more interested in a caffeine-&gt;theobromine video, rather than the other way around.

jason black

I was going to mention it, but i decided not to. It was hard to use a soxhlet because the powder was super fine and would have prevented proper emptying. I didn't have any celite or silica gel to mix it with either. Also, I decided to soxhlet extract piperine from black pepper. So, I didnt want to do two videos that were too similar.

Nile Red

Thank you so much for keeping science alive. Your videos are exemplary. Is there a reason you wouldn't use the soxhlet extractor in this process?

I'm OK with the late post. The quality really makes it worthwhile.

Roger Lee