electron multiplier tune for GC/MS

[biomass]

Hi all,
currently, I do the auto tune, and the electron multiplier tune cannot pass.
Electron Multiplier: Final Gain setting is incomplete (EM Voltage: 1400) The Final Gain cannot be set due to poor peak resolution (i.e. broad mass peaks) possible reasons include:
a) too many ions in the trap
b) Axial modulation too high or low (typical: 2~4 volts)
c) column flow too high or low (typical: 7.5ml/min~1.5ml/min)
d) Cal Gas pressure too high

I don't think a), because I bakedout the GC/MS, and for b) my axial modulation is 4volts, so it should be fine. for c) my column flow is 0.8ml/min. for d) I'm not sure, but the control and status window says the pressure is ok.

Currently, I have no idea about what should I do. (My GC/MS system is Varian 3900/saturn 2000

Thanks!

[Davidantony]

first adjust RF to minimum and also adjust cal gas.Then you tune only Electron multiplier only then you go through a full auto tune then also it is not passed you have to clean trap

[biomass]

Thanks! I minimum the RF and the also adjust the cal gas, but still cannot pass the electron multiplier.

first adjust RF to minimum and also adjust cal gas.Then you tune only Electron multiplier only then you go through a full auto tune then also it is not passed you have to clean trap