D,L-amino acids
fperini@unmc.edu
Thu, 23 Sep 1999 11:59:16 -0500
About two months ago there were two requests for D,L-amino acid
separations.I had done
some work in the past,but with cumbersome methods,but I was
interested,since,at times,I have
had to analyze peptides with D-amino acids
I found two types of analyses in the literature,one making use of the
Marfey's reagent and
the other of precolumn OPA-N-Ac-Cys.I had tried the latter with some
success.
The Marfey's worked but it was limited to a few amino acids,as reported.The
OPA method,
according to Nimura and Kinoshita:J.of Chromat.352,169-177(1986) had worked
in the
author's hands very well.Only D and L-Lys did not resolve.I tried several
columns,since the
one listed ,Devolosil ODS,was not available.They,also,used methanol,which
gave me back
pressures of over 3000 psi.,at a lower flow rate.
I tried acetonitrile,and I got extremely sharp peaks with an old
Ultrasphere column.There was
some resolution,but not enough if the percent of D-a.a. was low,as
expected.,for S,A,L and K.
All other amino acids resolve well,but a few overlapped.So,this method may
work with the right column,or if not all amino acids are present.Has anyone
else done better?
Fulvio Perini,Ph.D.
986805 Nebraska Med.Cnrtr.
Omaha,NE 68198-6805
ph:402-559-6184/FAX 402-559-4651
fperini@unmc.edu