Very annoying background noise

[leo1352]

Hi all,
I have started using LCMS-QTOF Brukerfor three months and we have a problem on the instrument background in positive mode. there are two masses of 86 and 114 at 10*4 magnitude that are persistently present in the system using a HILIC column. We use ACN in B and water(MS grade) in C with formic acid 1% on both solutions and also 10mM Ammonium formate in solvent A. I have been washing the entire system with those solutions but the problem still persists. We also use a ramping approach for the solvents A and B.
Do you have any comments and ideas of how to get rid of these stubborn compounds?
Thanks for your help

[sav]

It's not so bad (10e4). The background ions in the low mass range (<300m/z) is normal for ESI. If they don't interfere (interference with analyte ions, ion suppression etc.) - it's not problem

Look this:

http://sea.rice.edu/sites/sea.rice.edu/ ... dducts.xls
http://www.cigs.unimo.it/CigsDownloads/ ... 20Trap.doc