Injecting a gas like methane onto a GCFID

[seamoro]

I have to setup a method for methane analysis. I must inject from a gas tight syringe the methane gas. I assume i cant just direct inject into normal gc injection port otherwise the gas would escape?

[Peter Apps]

Where would it escape to ? A GC inlet has to be gas-tight in order to hold the head pressure that drives carrier gas through the column.

Peter

[Johnny Rod]

Better to use a gas sampling valve, that way it goes into the carrier consitently, and you get considerably better precision.

[antonk]

You can even sample a room air with gas-tight syringe and analyse methane produced by living organisms.
Just properly clean carrier gas and FID hydrogen from hydrocarbons.

Sampling valve is required for both high throughput and required high reproducibility.

[chromatographer1]

http://www.vici.com/vval/vval_gc.php

[jdezeeuw]

what detector will you use? What other components can be present?
This all determines what separation you need.

TCD will respond to everything, so you NEED a higher retention for methane. If A FID is used, and you have also C2-C3 there, you also need a xcolumn that separates the C2+ components from your methane.

j de zeeuw, Restek corporation