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				How to purify basic peptide
				Posted: Thu Mar 06, 2008 8:13 pm
				by proteinpeptide
				My peptide is very basic, if I use 0.1%TFA of H2O/ACN, I got very broad peak and coming up very early, do you guys have some suggestions to improve my purification? Thanks!
			 
			
					
				
				Posted: Thu Mar 06, 2008 9:20 pm
				by Kostas Petritis
				You'll get more retention by using a higher perfluorinated homologue (i.e. HFBA or NFPA) and you'll get better peak shapes by using a well encapped silica stationary phase or even a polymeric one...
			 
			
					
				
				Posted: Thu Mar 06, 2008 9:46 pm
				by Uwe Neue
				My suggestion is to use ammonia at pH ~ 10 with a packing stable at this pH, specifically XBridge C18
			 
			
					
				
				Posted: Fri Mar 07, 2008 8:52 am
				by danko
				Hi proteinpeptide,
If I understand you correctly, you’re aiming at purification of a peptide and not analysis for it.
I know, sometimes these two goals could be combined, but if you’re planning to use the peptide for further investigations etc. the TFA is a bad choice – it could be extremely difficult to get rid of TFA once it got in contact with the peptide/protein.
If I were you - for a first test/examination - I would look at Uwe’s suggestion. It shouldn’t take that much time to do a couple of experiments and evaluate the results.
If purification is the main goal I would consider HIC one of the possibilities.
Best Regards
			 
			
					
				
				Posted: Fri Mar 07, 2008 4:06 pm
				by proteinpeptide
				Thank you guys