Chromatography Forum

In our GC (Agilent 7890), our columns cannot separate some low boiling point chemicals, so we have been collecting the gas leaving our GC via the split vent with a Tedlar bag. In order to do this, we needed to remove the activated carbon filter material from the split vent trap, and we replaced it with quartz wool. This was not a suggested modification from Agilent, however it helped greatly for our analysis. I am wondering if anyone else has ever done this, and what was their experience with it? We lately have been having a lot of pressure issues with that inlet, where the pressure exceeds set pressure at high split ratios, and I am worried that removing the split vent trap filter may have caused this issue.

the filter in the agilent split vent line is primarily to trap higher boiling components from your sample and prevent contamination of the EPC module.
Since you are analysing volatile samples, removing the trap should not be an issue.
Just ensure the associated tubings and split vent trap holder are pressure tight.

Absolutely could be a problem. If I were you, I would have a spare split vent controller on the shelf ready to go.

Best regards,

AICMM

Are you injecting the tedlar post injection? Is it on the same instrument? I'd look into a programmable inlet like a multimode so you can start cold and ramp fast for heavier volatiles without the need for a second injection.