Chromatography Forum

I have a Molesieve 5A packed column in a HP 5890 TCD I am about to bring up. Does anyone know what temp (and time) i should bake it at to condition the column. It is brand new and I dont have a method made yet for my analysis, so I was looking for a good ballpark number that would be okay for column conditioning.

The bake-out should be at approx 20 degrees above the temperature of your sample method (at least that is the way I have always done it). I am going to be analyzing oxygen and hydrogen samples in a gas stream. I don't have the method programmed yet, but that is what we intend to use the TCD to analyze to give a better idea of around what temperature you would suggest

djpegram,

You should be able to comfortably take your MS column up to 200 C without any significant effect but you might have to leave it there for a while to get it clean.

By the way, the forum is littered with posts about the difficulty of doing hydrogen and oxygen with the 5890 TCD. I would strongly suggest an HID but I am strongly biased in this view since I make an HID for 5890's. I can provide more information if you would like to contact me at aicmm at flash.net.

Best regards.

Ok, with this column and permanent gases, you'll likely be doing the separation as cold as you can, maybe 35C. We routinely condition this column for this application at 280C anywhere from an hour or so to overnight. You need to get it hot to get the separation, then repeat the conditioning if you see loss of resolution. If you have valves in the oven, I'd check the valve rotor temperature specs. Some of them can't go this hot (been there).