Problems in MRM mode

[danielamecro]

Hi all,
I have problems with my GC-MS triple Quad system.I have change the argon tank and i loss the sensitivity from run to run.Next day,the first analisys is good but the areas from pesticides decrase gradual for 10 replicates.I clean Q1 and Q2 but the problem is still theare.
In SIS mode all is OK.For exemple:HCB,the ion 284 in Q1 have the same sensitivity for 10 replicates.In MRM mode,decrease the area from 2MG counts to 100 kcounts.
What can i do?
Please advice!
Thanks

[Alp]

Leak?
Did you turn the tank on (valve)?

[sav]

Are you purge gas line (argon) before installation?
Purity of argon?

[danielamecro]

Are you purge gas line (argon) before installation?
Purity of argon?

I purged the line but unable to check the purity.Argon is 5.0
I changed the forline pump,i assumed it could not evacuate argon in Q2.The next step is to change the tank.
Thanks
Daniela

[sav]

I changed the forline pump,i assumed it could not evacuate argon in Q2.

Vacuum/pressure in Q2 - ОК?

The next step is to change the tank.

Advice: purge Q2 with argon (12-48hours; just don't close collision gas valve) before the next step. This may help you.

Best wishes, Alex.

[danielamecro]

vacuum in Q2 is OK
i appreciate your advice
Thenk you!
Daniela