Chromatography Forum

Hello.
We are using ZIC-pHILIC column for LC-MS detection of cellular metabolites.
After injecting cell extracts several times, my standard sample shows peaks with Mg ion adduct. E.g. for ATP the MgATP peak intensity is several times stronger than ATP itself.
I tried to wash the column with 95% water (5% ACN) for 2 hours, but it didn't help.
How to wash the magnesium from the column?

I would add about 100 mM- 1 M of a volatile salt in the same mobile phase that you are using and would try again... Do not connect the column to the MS during the column cleaning...