Possible suggestions: 300 A ion-exchange matrix from almost any supplier,
Zorbax or Rainin or anybody else. Use an anion exchanger at pH 5.0 or close to
that, elute peptides in ammonium acetate gradient, in water or in 10 to 20%
organic. This will work to get the ones with full-length arg. The
Aspartamide-columns from the NEST group are another excellent choice.
Another gradient can use Acetic acid/Triethylamine pH around 4 to 5.5 for aninon
exchange, use ammonium acetate to elute peptides. For comparable
cation-exchanger use a pH of about 6.00 or 7.00 or 8.00 use ammonium bicarbonate
as an eluent.
Use a Poros-Perseptive column hooked to your HPLC. The prepacked columns are
expensive, but you can pack your own. The 10 u cation-exchanger should be able
to handle upto 40 mg loads, provided that the contaminants are well resolved
(actually I have switched most synthetic peptide purifications to the BioCAD).
These peptides are small and they should bind to the more robust and stronger
Dowex or Amberlite type matrices. The advantage with these resins is that one
can use neat acids or bases and essentially recover salt-free peptides. BioRAD
has a very nice manual that discusses several of these resins and their
applications in fair detail.
Finally, you could use NaCl for elution from ion-exchange columns and then
desalt the peptide on a Sephadex G-10 column equilibrated and developed in 0.1 %
TFA/10 % acetonitrile. Follow abs at 220 nm.
Hope this helps, Gautam