by
AICMM » Tue Nov 27, 2007 12:07 am
jf,
SGE makes the low volume union (PN 073550) which I used long ago with mixed results. Valco makes low thermal mass union (EU 0.5T) which I have used a bit with good results and know of someone who swears by it. Not deactivated though. Gerstel makes Graphpak 3D/2 which I have not used but I have worked with their other connectors and had very good luck. Agilent has "Ultimate union" which I have not used and was, frankly, shocked at the price. The person I know who has used this swears by the Siltite ferrules even under heavy oven cycling.
In my applications, I use a transfer line from injection valve to column (either packed or capillary) and I use a transfer line (usually) from column to detector. Most of the time I use a Swagelok 1/16 in union with graphite vespel ferrules and I install one column completely in the other. Most of my work, though, is not really high termperature stuff. I am, however, accutely sensitive to air leaks (helium ionization work) and I rarely have trouble with this set up.
Good luck and best regards.