Chromatography Forum

Hi to all, I work with an Agilent GC-MS and recently i have changed gas carrier from helium to hydrogen.
Agilent technician has already performed PMOQ.
But today i have found a problem with filter (trap) --> if I use the filter the N2 is high, if i bypass the filter H2O is high.
Another problem is that all the compound peaks with hydrogen has different retention time despite with helium --> someone knows how to do an analysis in scan with opelab2?

thanks in advance

Check to see if the filter was purged with Nitrogen or Helium before it was shipped. If it was Nitrogen then you will see a high Nitrogen in the background until it has all flushed out of the trap, it can take several days for it to drop to normal levels.

You will have to do a lot of experimenting with the flows and oven temperature ramps to bring the retention times with hydrogen near those you had with helium, and some close eluting peaks may even change order, it takes a lot of work to find them all the first time.

Sorry I never used Openlab, only MSDChemstation and MassHunter.