reuben carr - 25-3-2005 at 02:53
I was wondering whether you may have suggestions on a quick and easy method to remove ammonium formate from a mixture of a low molecular weight
aminoacid and ammonium formate mixture. I'm currently using Dowex ion exchange chromatography. Any other suggestions would be appreciated
Thanks,
Reuben
chemoleo - 25-3-2005 at 07:14
HPLC, reverse phase should work, too, although I'd prefer ion exchange as well, if it works. You could do TLC, but that is hardly practical for
large scale stuff.
You can't use dialysis (unless the these are short peptides, not single a.a.'s), nor gel filtration, nor buffer exchange column it seems
because the molecular mass difference is not big enough for these techniques.
[Edited on 25-3-2005 by chemoleo]
Madandcrazy - 1-6-2005 at 06:54
The extraction of ammonium format from HPLC liquid should walk.
HCOO- NH4+
-->
HCOONH3 + H+
What have the molecular mass difference to do with the dialysis ?
azaleaemerson - 1-6-2005 at 08:27
You could add a bit of a heavy hydroxide like calcium hydroxide and drive the ammonia off by bubbling in air. Then I think that calcium formate has
poor water solubility and can be filtered off.
BromicAcid - 1-6-2005 at 09:57
You may think that calcium formate has a low solubility in water, but that won't make it true. Hence the use of formic acid to remove calcium
carbonate scale from boilers and the inside of hot water tanks, the formic acid reacting with the calcium carbonate to produce the relatively soluble
calcium formate which can then be flushed out of the system.
unionised - 1-6-2005 at 11:45
IIRC lead formate isn't very soluble, but you would need to check.
Did you think about ppting the amino acid as some salt and filtering it off?
12AX7 - 1-6-2005 at 14:11
Hm formate = methanoate, I'd think a lot of those are soluble. Lead and calcium acetate (ethanoate) are, after all. It's a smaller,
stronger acid than acetate so should be more (or less? hm..) soluble.
Tim
unionised - 4-6-2005 at 07:31
Thanks for telling us all that.
Anyway, I looked it up, 1.6g/100 ml @15C.