Simple translation of GC methods from helium to hydrogen carrier gas

I had a presentation at PittCon last year discussing using hydrogen and nitrogen carrier gases for the gas chromatography of organochlorine pesticides.  I showed how you can substitute nitrogen at the same linear velocity as hydrogen, while keeping the same oven temperature program used for hydrogen and get a similar chromatogram, albeit with wider peaks and less peak separation for nitrogen.  One thing that allows that substitution to be successful is the excellent selectivity of the Rtx-CLPesticides GC column for organochlorine pesticides.

Jaap de Zeeuw challenged me to do a similar experiment and go from helium to hydrogen, taking a look to see if any loss in separation occurred, since presumably hydrogen would drop below sub-optimum average linear velocity.  I present the work here and I’m happy to say there was no real loss in separation.  I used a Restek Method Translator to match the hydrogen linear velocity with my original linear velocity from a Speed Optimized Flow for helium and then kept the GC oven program the same.  As you can see, the chromatograms are almost identical for helium and hydrogen methods, although the responses drop by about half when using the Agilent µ-ECD with hydrogen.

This approach should allow an easier entry for people making the switch from helium to hydrogen carrier gas for GC.

More later...