Splitless purge flow HS-SPME

[burritoblu]

Hello everybody,

I am running a few GC/MS SPME headspace methods in Splitless mode. I have a fiber conditioning station, so I do not need to condition the fiber in the inlet post-run. For example I let the fiber in the inlet for 2 minutes and then I move it to the conditioning station.

I have some questions regarding the "Purge flow to split valve" parameter. I can set the flow (default is 50 ml/min) and the minutes.
If I understood well, after X minutes, a helium flow of X ml/min is sent to the split valve. This is supposed to empty the septum from residuals solvents and compounds (tell me if I am wrong).

1° Do I need to purge the inlet with a high flow even if I am using a solvent-less techinique like HS-SPME ?
2° Now I have set it to 50 ml/min after 2 minutes. Do you think it makes sense to reduce the flow to save gas? (15 ml/min which is equal to my gas saving schedule)

Thank you very much

[Peter Apps]

The split flow has nothing to do with "emptying the septum" - it flushes the inlet volumes. It is the septum purge flow that is supposed to stop emissions form the septum from reaching the column.

Purge the inlet at 50 ml/min for 5 min after removing the SPME fiber, then go to gas saver flow rates.

Peter

[burritoblu]

The split flow has nothing to do with "emptying the septum" - it flushes the inlet volumes. It is the septum purge flow that is supposed to stop emissions form the septum from reaching the column.

Purge the inlet at 50 ml/min for 5 min after removing the SPME fiber, then go to gas saver flow rates.

Peter

Oh yes ! I wanted to say inlet, not septum.
Thank you for the explanation Peter