By philip on Monday, June 21, 2004 - 10:46 am:
Hello, recently i have been having trouble with the analytical HPLC of a couple of peptides which we have synthsized. I am using chromquest,c18 column and UV 3000 detector to analyze them. These peptides do not show up at all during the run even at 214nm. Concentration used are 1mg/ml. The HPLC shows the solvent peak and rest of it is a straight line. There is no problem with the instrument as it is working for other compounds.However, they do show up on mass spec by which i am able to conclude that the desired peptide is present.Has anyone come across such problem where the peptide do not show up at all on the HPLC?
By Uwe Neue on Monday, June 21, 2004 - 02:34 pm:
They could either be unretained or strongly retained. You appear to inject the peptides in an organic solvent. Is it possible that they are in the solvent peak? Alternatively, is your C18 column suitable for peptides, and what is your pH etc.?
By philip on Wednesday, June 23, 2004 - 10:23 am:
Thanks for the reply. We figured out that the desired peak was in the solvent peak as you have mentioned here. So we have changed the gradient which we were using. Now its working fine.
Thankyou.