Molsieve separation for O2 and N2

[bijish]

We have an agilent 7890 natural gas analyzer with Hayesep Q (3 ft and 6 ft), Molsieve 13X 10 ft and PONA column 50 m. TCD detects O2, N2 and methane from Molsieve column, but the separation of O2 and N2 is poor in Molsieve 13X. Could someone help?

[kubowicz.tomasz]

Hello

Perhaps you need to regenerate Molsieve column. Common way is baking out in ~300°C for couple of hours.

Regards

Tomasz Kubowicz

[muGC]

Or perhaps your valve timing is wrong and the oxygen is not getting on to the Molsieve. It is possible to lose the oxygen peak as it is the first to elute from the Molsieve column with your method.

[bijish]

Or perhaps your valve timing is wrong and the oxygen is not getting on to the Molsieve. It is possible to lose the oxygen peak as it is the first to elute from the Molsieve column with your method.

When ww inject air for O2 calibration, we detect oxygen and nitrogen peaks, but poor separation...

[Jonezy_Lothos]

Sounds like you need to bake out your molsieve. Be sure to remove it from the GC, you valves can not take the heat. Make sure you bake it out with flow.

have fun,

Jones

[isalas]

You can also move from Molsieve 13x to Molsieve 5A. This should give you a better separation of components.