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- Posts: 3
- Joined: Thu Jul 01, 2021 3:39 am
I am running into this problem with my LC-MS (QQQ) system, where I see ghost peaks in my MS2 scan. The ghost peaks have high intensity so I could not get a chromatogram of my standards. I tried a few things but the peaks are still persistent in terms of m/z and intensity, and the peaks looked the same when using gradients or not. I removed the column and guard column, disconnected the UV detector, disconnected the column thermostat, changed solvent bottle and flushed the system with isopropanol, but nothing worked. So far, I cannot even tell if the peaks are caused by contamination in the mobile phase (something stuck in the LC) or contamination in the MS unit. The only difference I observed for the ghost peaks is when switching from ESI+ to ESI- the m/z and intensity changed. Could someone please help me? Thanks!