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Headspace GC - problem with PCE reproducibility

Posted: Thu Nov 08, 2018 9:03 pm
by Lehonet
Hello

I would like to ask about the problem with reproducibility in headspace GC. I am analysing PCE in water samples. I first prepare sock solution by dissolving PCE in methanol and then inject it into water.

I have good reproducibility of MeOH peak, but a bad one in the case of PCE.


SHS conditions:

Oven: 80 °C
Manifold: 100°C
Transfer line: 110°C
Loop fill time (min): 0.1
Loop eq. time (min): 0.1
Equlib: 3min

GC conditions:
Injector: 120°C
45°C (hold 1min); 175°C (30°C/min) (3min)

Is there any changes I can make to reach good reproducibility?

Any advice would be greatly appreciated thanks.

Re: Headspace GC - problem with PCE reproducibility

Posted: Thu Nov 08, 2018 9:06 pm
by rb6banjo
Keep in mind that not everyone on this forum knows what you're talking about when you use acronyms. What is PCE?

Re: Headspace GC - problem with PCE reproducibility

Posted: Thu Nov 08, 2018 11:12 pm
by pacerlaser
I think they are referring to tetrachloroethylene, also know as perchloroethylene or PCE.

Re: Headspace GC - problem with PCE reproducibility

Posted: Fri Nov 09, 2018 4:45 am
by Lehonet
PEC means perchlrethylene, tetrachlorethene. Sorry

Re: Headspace GC - problem with PCE reproducibility

Posted: Fri Nov 09, 2018 9:22 am
by AaronAIT
Your equilibration time of 3 minutes seems very low. Is this allowing enough time for your analytes to reach equilibrium?

Re: Headspace GC - problem with PCE reproducibility

Posted: Mon Nov 26, 2018 9:04 pm
by Peter Apps
What column ate you using ? - length, diameter, stationary phase ? and what are the carrier gas flow rates and split ratio ?

Peter