No fragmentation in ESI
Posted: Tue Feb 19, 2019 6:16 pm
Dear all,
As you can gues from my title I do not experience any fragmentation in MRM mode while tuning.
My normal tuning for an appropriate MRM method looks as follows (maybe there are already a few flaws in there):
1) I directly infuse the analyte of interest by a syringe.
2) tune the machine i.e. I regulate cone voltage, capillary voltage, LM, HM and so on
in between I do several MS scans to see if I achieve improvements regarding sensitivity
3) If my sensitivity is good enough I switch on the collision gas which gives a hissing sound. The signal of my precursor ion gets lower depending on the intensity I set for the collision but I cannot see any fragments.
We have the same machine a second time (waters quattro micro API) and my approach works on it i.e. I do see fragmentation of the exact same saple.
Do you have any Ideas? Or some advice?
As you can gues from my title I do not experience any fragmentation in MRM mode while tuning.
My normal tuning for an appropriate MRM method looks as follows (maybe there are already a few flaws in there):
1) I directly infuse the analyte of interest by a syringe.
2) tune the machine i.e. I regulate cone voltage, capillary voltage, LM, HM and so on
in between I do several MS scans to see if I achieve improvements regarding sensitivity
3) If my sensitivity is good enough I switch on the collision gas which gives a hissing sound. The signal of my precursor ion gets lower depending on the intensity I set for the collision but I cannot see any fragments.
We have the same machine a second time (waters quattro micro API) and my approach works on it i.e. I do see fragmentation of the exact same saple.
Do you have any Ideas? Or some advice?