Phase collapse for Cyano columns

[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.

[tom jupille]

CN phases are generally quite hydrophilic. Dewetting should not be a problem at *any* aqueous/organic ratio.

[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.

[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.

[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.