do you cap your spetum purge vent and split vent ports?

[zimanli]

Greetings.
We have another GC/MS in another group. I noticed that they use swagelok cap to cap their spetum purge vent and split vent ports. I do not understand. If that is the case, where does vent gas go? even though it is splitless mode, there is ~3 ml/min purge gas is going. Please forgive me if it is a stupid question.

Thanks a lot!
have a great day.
ziman

[Ron]

I have seen this done in the past, and the people doing this were unhappy with the performance of the instrument. After I removed the caps, set up a proper method, and explained how splitless injection works they were much nappier with the instrument perfomance. The GC should never be operated with the split and purge vents capped.

[Peter Apps]

Hi Ziman

While Ron is quite right that the normal functioning of the GC depends on having the vents open, it could also be that the other group have some alternative inlet plumbing installed. I have an experimental headspace set-up on an Agilent 6890 GC with the vents plugged. Why not ask the other group ?

Peter

[zimanli]

Ron and peter, thank you very much for your response. I asked them, and they told me they borrowed the GC/MS from MIT, and it came like that. They do have a special headspace plumbing into the machine. You guys are right.

ziman