Chromatography Forum

Hi,
When running a new sample matrix what type of precations do you take to prevent contamination? LC QqQ instrument.

Obviously I would start a dilution series to investigate signal. Would you run full ES+ and ES- to check background in addition to target analyte mass? Also remove particles by spinning 10 000 rcf or filtering of sample 0.22um.

My fear is that I have crap that i wont see at high conc if I just scan for target analyte and will contaminate instrument with matrix. So what do you suggest for a new unknown sample, any general recommendations!

I usually just start at a 1/1000 dilution through a 0.22 um filter (PTFE or Millex depending on the solvent) then go up 10x each time while running a scan usually around 100-1000 m/z, then do an EIC to check if I can see my target at that conc. Inspect the source after the run to see if there's any fouling.

I usually just start at a 1/1000 dilution through a 0.22 um filter (PTFE or Millex depending on the solvent) then go up 10x each time while running a scan usually around 100-1000 m/z, then do an EIC to check if I can see my target at that conc. Inspect the source after the run to see if there's any fouling.

Thanks for the reply this was helpful! I will start out along those lines and see what the signal looks like.