purification of FID gasses

[Peter Apps]

Does anyone have specific recommendations for purifying the hydrogen, air and nitrogen to an FID ?. Does charcoal remove methane or not ?

This is for an investigation of the properties of the detector itself, so organic background has to be as low as it possibly can be. If I have to I can run hydrogen through a palladium membrane, and I presume that I could run the air over a catalyst to oxidise organics - does anyone have experience and recommendations with this approach ?

Thanks

Peter

[gcguy]

Peter,

We run our bottled hydrogen and helium through moisture, oxygen and hydrocarbon filters. The air, from a compressor, we pass through only a hydrocarbon filter. Nitrogen goes through a hydrocarbon filter as it only used as make up gas on FID. All of these are proprietry filters and are as the instrument maufacturer recommends. Not sure of the mechanism for the oxygen filter but the other two are mol sieve and carbon. I have seen various devices for cleaning up gas supplies but the one we use suit our needs so I havn't done much investigation on them.

GCguy

[chromatographer1]

If your work is temporary in nature perhaps you could lease air and hydrogen generators.

Zero air generators will remove organics from air but carbon dioxide may result. There are traps for CO2 but I don't know how effective or durable they are.

There is no trap for methane other than using an oxidizing purifier which forms CO2.

If you invent one you can make a fortune. I will market it for you, gladly.

There are good traps for helium and hydrogen which remove very low levels of other gases. There are generally based on heated metal catalysts. Other indicating traps use exotic chemistries.

Good luck in your research.

best wishes,

Rod

[HbJ]

Regarding my recommended setup for gas purification please see my answer in http://www.sepsci.com/chromforum/viewtopic.php?t=5990

Regarding the purification of air from CO2 please see http://blog.newpointgas.com/index.php?id=7

Hope this helps.