By Basil on Wednesday, July 14, 2004 - 04:12 am:

Does anyone have a method to control presence of related aminoacids in Valines or Leucine by HPLC using DAD?. Any bibliographic reference would be appreciated.

Thanks

Basil

-------------------------------------------------------------------------------------------------------
By SIELC_Tech on Wednesday, July 14, 2004 - 10:18 am:

Check this out. The method describes analysis of underivatized aminoacids by mixed-mode HPLC:
http://allsep.com/makeCmp.php?cmp=Cmp_098

-------------------------------------------------------------------------------------------------------
By Basil on Thursday, July 15, 2004 - 01:18 am:

Thanks but with a DAD ? I'm not able to detect the compounds and I don't have an ELSD detector !!!

Basil

-------------------------------------------------------------------------------------------------------
By SIELC_Tech on Thursday, July 15, 2004 - 09:16 am:

Basil,

In the application above you can replace TFA with sulfuric acid and analyze aminoacids at 205, 210 nm and see carboxylic group. Sulfuric acid is transparent at 205, 210 (with high quality acid you can even go lower). You don't need ELSD in this case.

-------------------------------------------------------------------------------------------------------
By Basil on Friday, July 16, 2004 - 04:23 am:

Does anyone have a method with an MS detector to control Related Substances in AminoAcid ??...

Do you belive that I can use this method with the MS detector since Aminoacids have a good response with ESI MS detector ??

-------------------------------------------------------------------------------------------------------
By SIELC_Tech on Friday, July 16, 2004 - 08:20 am:

BAsil,

You can use TFA, formic acid, ammonium formate, ammonium acetate with Primesep columns. What else besides valine and leucine you have in your mixture?

-------------------------------------------------------------------------------------------------------
By Basil on Monday, July 19, 2004 - 12:17 am:

Hi,

This is the real problem. I work in a fine chemical company which makes API for pharmaceutical company. Our last step in the synthesis route use valine to obtain the final product. So we need to control every possible related substance in valine and that's why I can't use TLC method from USP or EP, which does not give to us any specific information. We think that we could find all kinds of aminoacids compounds like (leucine, isoleucine, and similar).

I would try to use this method with MS and I woult tell you ny results.

Thanks for all

Basil