Gas Saver Mode - How to use it correctly

Hi Peter,

Gas saver is recommended, the only time you really need full split flow is for injection. Gas saver is usually configured to switch on after 2 minutes. For example, take a 100:1 split, your total flow would be something like 110 ml/min on the inlet at 1ml/min column flow constantly. With gas saver, it will only be that high at the time of injection for a 2 minute period. After that, the flow will be approx 24ml/min for the run and even in standby. A substantial savings in gas supply.

Regards

James

Good morning,

What if I use splitless injection, should I turn gas saver mode on?

Thank you.

Yes.

Splitless changes the flow in the liner during the Splitless time. At the Purge On time the flow needs to be sufficient to rapidly sweep any residual sample from the liner. I recommend 60ml/min since most liners are about 1 ml and that flow sweeps the liner in 1 second.  If you do not use Gas Saver mode, that purge flow will be on the entire run.  Like this:

During the first 0.75 minutes of the run, the liner flow will equal column flow - 1.2 ml/min into the column and into the MS.

At 0.75 minutes, the liner flow will be 60 ml/min.

At 2 minutes, the total inlet flow will be 20 ml/min. This total flow is the lowest recommended total flow setpoint to ensure that no air, no oxygen, can migrate into the inlet and column.

From the 8890 Operation Manual page 81.usermanual-gc-operation-8890-g3540-90014-en-agilent.pdf

Thank you very much for the answer.

Would these parameters below be acceptable?

The column is 30mx250umx0.25um (Agilent P/N 19091S-433UI).

Oven is at 40ºC.

Injecting 1uL of dichloromethane.

Liner's volume is 911uL.

Detector is MS.