Chromatography Forum

I'm trying to install a 530 um capillary column on an HP 5890 Series II Plus. The ferrules (presumably graphite) are old stock; I'm not sure they're the right size for the column nut. They accept the column tightly, but the ferrules fit into the nut with some wiggle room. Do these graphite ferrules expand when compressed? I'm running hydrogen as the carrier gas, and kind of want to make sure I have everything right. I have the manuals, but they don't mention anything specific to sizes, gaps, etc.

Image link:

http://imgur.com/3SjcT

Click on the image to enlarge it; note there's a bit of a gap between the ferrule and the ID of the capillary nut.

TIA!

Pure graphite ferrules are very soft, and will squash to conform to whatever the shape of the fitting is. No matter what ferrules you use you must always leak check all your fittings before you run the GC - leaks are a major source of oxygen and water that destroy columns.

Peter

Should be fine, don't tighten them any more than needed to stop you pulling the column out gently.