Our chromatography was done using an old C18 PTC column (an Altex
(Beckman) C18 ODS 4.6 x 150 mm) that we had used for PicoTag amino
acid chromatography--so not the 5 micron, 300 angstrom particle columns
designed for proteins/peptides.
We ran isocratically with 85% methanol, 15% 0.1 M NaH2PO4 adj to pH 2.5.
Flow was 0.7 ml/min, back pressure was fairly high. We had fairly good
separation. You might want to drop the % methanol by 1 % or 0.5% to get
better resolution--it will depend on the hydrophobilicity of the column
material that you end up using. I don't think I would use a C4, probably
won't get resolution as well as on the C18 ODS.
Hope this works for you,
Deb McMillen
Institute of Molecular Biology
University of Oregon
On Thu, 8 Oct 1998, Laurent Boyer wrote:
>
> Hello everybody,
> I need to purify some Gramicidin D (from SIGMA no G-5002) : I would like
> to separate the different isoforms by RPHPLC (with a C4 column).
> I already tried with ACN/H2O and MeOH/H2O as mobile phase but
> unsuccessfully in both cases : No signal after column !! the peptide's
> maybe stuck into my column (?).
> Any suggestions (eluents, gradients, sample solvent...)?
>
> Thanking you in advance for your help,
> LAurent.
>