prole - 7-1-2006 at 14:10
Not sure if this post belongs here, or in Organic (because of the picolinate), but here's my question:
Is it possible, practicle, and feasible to isolate elemental chromium from chromium picolinate? It's available as a diet food supplement, with
questionable effects. If chromium can be isolated from it, then it would be useful.
Incidentally, I've read the picolinate is a by-product of tryptophan (Merch Manual online). Can this be converted back to tryptophan?
12AX7 - 7-1-2006 at 14:34
Well certainly, you can add HCl or H2SO4 and get the chromium salt and free picolinic acid (unless it complexes stubbornly, as chromium likes to do).
Or add heat until the picolinate is all but gas vapors, leaving you with something like Cr2O3 (which might be worse, since it's generally slow to
react).
Lemme see what picolinate is... hm probably does tend to stick to chromium pretty well. If you don't care about it, ashing will certainly get you
chrome oxide, but if you want to save the pyridine structure, I think you'll have to go with an acid. (An alkali dry distillation might yield
pyridine alone, for that matter.)
But really, to isolate chromium? Using a food-grade supplement seems an awfully low-yield, expensive, roundabout way to do it.
Tim
DeAdFX - 7-1-2006 at 14:35
Most dietary substances are a mix of other stuff or the caps contain a bunch of buffer crap or the compound you want is in mg quantities.. Unless
this is pure chromium picolinate powder.
If its pure chromium picolinate then it might be worth your time if not dont bother.
The_Davster - 7-1-2006 at 15:01
This is not as simple as one may think on first look, I thought a simple addition of HCl would get a solution of chromium chloride and a ppt of
picolinic acid, however upon checking some solubilities, picolinic acid is more soluble than the chromium salt.
If you were to acidify and then basify you should likely get a solution of sodium picolinate and a ppt of chromium hydroxide. Easiest method would
likely be to just heat it till you have chromium oxide(like tim said) if you do not care that you loose the picolinic acid structure.
What do you want to end up with anyway?
EDIT: What was I thinking...just add NaOH or another alkali hydroxide, the sodium picolinate shold stay in solution and chromium hydroxide should ppt
out.
[Edited on 8-1-2006 by rogue chemist]
chemoleo - 7-1-2006 at 17:16
Actually picolinic acid is quite an interesting substance itself.
Here's zinc picolinate
Apparently it's one of the body's main chelators, chelating most transition metal ions, and possibly molybdenum too.
Surely there are some other purposes to it? For instance, decarboxylation should give pyridine.... 
Also, I am sure there are easier ways to obtain Cr. I mean, look at the mass-percent of Cr, those are very small amounts!
Other sources are of Cr2O3 from pottery supplies, from which Cr can be obtained by thermite
Chrome alum is a widely sold crysallisating substnace for hobby crystal growers.
Also check this for properties of Cr(picolinate)3
Purple powder... not much soluble in H2o... mmmmh!
http://www.finechem-china.com/products-e1.htm
[Edited on 8-1-2006 by chemoleo]
IrC - 8-1-2006 at 01:41
Five cents worth of chromium for every thousand dollars worth of diet pills and hundred hours of work. Makes sense to me. Personally I would just
search ebay for emovendo or hamric and buy the metal at fairly low prices.
prole - 9-1-2006 at 07:10
In all my excitement I forgot to check the mass percent. I know that chromium is available at auction sites, but I'm really interested in buying
things OTC locally. Much of the fun is in seeing what one can obtain from everyday items.
I'm trying to get chromium to actually make chrome alum and the dichromates to grow as crystals, crystal growing being one of my science hobbies. OTC
can be quite expensive, and I'm usually open to spending the extra dough, but if yields are too low, then it's often not worth it. Thanks for
everyones' replies.