Running CSH column with 100% aqueous?

[sulee154151]

Can we run a Waters C18 CSH column with a 100% aqueous mobile phase without having any problem?

If not, what should be the minimum methanol or acetonitrile % in the mobile phase?

Thanks in advance.

[tom jupille]

AFAIK, should be Ok with 100% water.

[mckrause]

Unless your samples and standards are in 100% water you're not buying yourself anything with 100% mobile phase. I'd tend to run at least 5% organic phase and worry a lot more about the final solvent system of the sample.