I forward this message from Fr. Macko, since it seems to me of general
interest. I take this occasion to express my warmest thanks to everybody
who added their input to answer my question...

Sergine PONSARD
Laboratoire Ecologie des populations et communautes
Bat 362
Universite Paris XI
91405 Orsay cedex
France

>From: "Stephen A. Macko" <[log in to unmask]>
>To: Wolfram Meieraugenstein <[log in to unmask]>
>Cc: Matthias Gehre <[log in to unmask]>,
>        Sergine Ponsard <[log in to unmask]>
>Date: Sat, 29 May 1999 18:44:07 -0400 (Eastern Daylight Time)
>Priority: NORMAL
>X-Authentication: IMSP
>MIME-Version: 1.0
>
>Dear Gerd, Sergine and Wolfram:
>
>For some reason, I have not been able to respond to the
>discussion group- I get the messages compiled at the end of
>the day, and when I use reply, it has bounced the note
>back. In any case, I decided to send this to you directly.
>Please forward it to other interested parties.
>
>Mike Engel (at Oklahoma) and I have succesfully run 13C and
>15N on
>individual amino acids (and separated their stereoisomers)
>using TFAA/Isopropyl esters, on a Chirasil-Val column
>(Alltech). Arginine survives the derivatization and comes
>out quite late. TFAA/IP amino acids can be resolved on
>other polar phases, but not as stereoisomers. ASN and GLN
>do not survive the esterification, and come out with the
>ASP and GLU peaks. TMS derivatives do not destroy the GLN
>and ASN. When I run TFA amino acids, the furnace (I have an
>OPTIMA and ISOPRIME with respective interfaces) survive for
>a while , and then go catastrophically (they seal off, and
>my flow drops to zero
>
>References:
>Analytical Chemistry 63:370 (1991) (13C)
>Analytical Chemistry 69:926 (1997) (15N)
>
>We have been using the methods to arrive at isotope
>compositions of amino acids in meteorites.
>
>Best regards,
>
>
>Stephen Macko
>Department of Environmental Sciences
>University of Virginia
>Charlottesville, VA 22903
>804-924-6848
>804-982-2137 fax
>[log in to unmask]
>
>Dear Matthias and Wolfram:
>
>Mike Engel and I have successfully run 13C and 15N on
>individual amino acids (and separated their stereoisomers)
>using TFAA/Isopropyl esters, on a Chirasil-Val column
>(Alltech). Arginine survives the derivatization and comes
>out quite late. TFAA/IP amino acids can be resolved on
>other polar phases, but not as stereoisomers. ASN and GLN
>do not survive the esterification, and come out with the
>ASP and GLU peaks. TMS derivatives do not destroy the GLN
>and ASN.
>
>References:
>Analytical Chemistry 63:370 (1991) (13C)
>Analytical Chemistry 69:926 (1997) (15N)
>
>
>Stephen Macko
>Department of Environmental Sciences
>University of Virginia
>Charlottesville, VA 22903
>804-924-6848
>804-982-2137 fax
>[log in to unmask]
>

Sergine PONSARD
laboratoire d'Ecologie des Populations et Communautes
UPRESA 8079
Batiment 362
Universite Paris XI
91 405 Orsay Cedex
France
Tel : 33 1 / 69 15 56 91