[l.alvarez]

Hello,
i want to quantify the L-glutamate concentration in a fermented broth, the medium has high ammonium and glucose concentration. i observed, in thin layer chromatography developed with ninhydrin, that the medium contain almost only glutamate and very low traces of other amino acids.
  Now i want to isolate the glutamate for a spectroscopy assay with ninhydrin, because the other amino acids can react.
we have no access to a HPLC, but we have silica gel.
  If someone can give me a clue of how to figure this out.

PS: sorry about my English.

[Arkcon]

Off the top of my head, I wouldn't use a polar matrix to pour a purification column for an amino acid.  If you just need a rough quanitification, you can try to make a dilution series of standards, and run them on the same TLC plate.  If you need better, you can try to Google "L-glutamine chromatography" and you might find some reference with equipmnt you have, buried among all the HPLC methods.

[Babcock_Hall]

It is sometimes possible to separate an amino acid with a negatively charged side-chain from other amino acids that have a neutral side chain via classical ion-exchange chromatography under carefully controlled conditions (careful choice of pH and solid phase).

[l.alvarez]

Arkcon, our first approach was determine the concentration on TLC, but now i need something more accurate.
i was thinking in something like differential precipitation of amino acids, is that possible?,  In the other hand i have DEAE cellulose for ion-exchange chromatography, but my doubt is if i can separate aspartic acid from glutamate in this kind of chromatography (the R-pK  it is very similar).