Dealing With High Background For Non-Target Analysis
The projects I am currently working on deal with attempts to perform non-target analysis with a QTrap 4500. Our intention is to use the Enhanced MS scan coupled with EPI/MS3 scans and library comparisons to identify unknown compounds in samples, however background ions from our solvents are at much higher levels than even mg/L level standards obscuring any samples outside of MRM mode.
What ways might there be to mitigate this high background and find the unknown compounds in our scans?
Attached are a scan of a DI water blank (left), and a scan of a high concentration sample of nitroguanidine (right) (m/z = 103). The solvents used are water from a MilliQ (with LC-Pak) machine, and B&J LCMS grade methanol, both with 10mM Optima-LCMS grade ammonium formate.