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Phase collapse for Cyano columns
Posted: Mon Apr 06, 2009 4:14 am
by mohan_2008
I am using a mobile phase with the composition 50:50 Water: Methanol in a certain method with Cyanopropyl stationary phase.
I do not know if this composition "dewets" the Cyano phase.
I also am trying to understand the best mobile phase composition that uses the Cyano phase without any phase collapse.
Can you give me some examples that are optimal for using CN phase.
Posted: Mon Apr 06, 2009 9:58 am
by tom jupille
CN phases are generally quite hydrophilic. Dewetting should not be a problem at *any* aqueous/organic ratio.
Posted: Tue Apr 07, 2009 12:33 am
by mohan_2008
This might be contrary to an argument presented by Dr. Uwe. He said that Cyano phases collapse under intermediate polarity solvents.
I was trying to understand if my mobilephase combination presents this problem.
Posted: Tue Apr 07, 2009 12:50 am
by Uwe Neue
No, I did not say such a thing. Cyano columns are not subject to dewetting. Cyano columns can die for many reasons, from hydrolysis to voiding, but "phase collapse", better called dewetting, is not one of these things.
Posted: Tue Apr 07, 2009 3:34 am
by mohan_2008
Dr. Uwe,
I am sorry. you said that the "packed bed collapse" can occur in intermediate polarity solvents - not the phase collapse.
Can you please let me know, what are some of the common solvents that I can avoid to prevent this.