An Improved Blowdown System for GC Vials

The older blowdown system described above works well, but is a little inconvenient if you want to blow down lots of individual GC vials. So we built a second system, shown above. GC vials sit in small holes at the end of plastic (Delrin) trays, which slide in and out of an aluminum sleeve. To use the system, you pull out a tray, insert the GC vial, then slide the tray in until the vial is position under the N2 nozzle (a simple ceramic tube), where the solvent is evaporated. If you want to add more solvent ... just pull out the tray, add the solvent to the vial, and push it back in. Gas flow to each position is controlled independently via a miniature air control valve (they cost about $20 each and are available through McMaster-Carr). The valves are mounted on an anodized alumnimum 'air distribution manifold', and connected via teflon tubing. This system is a really big improvement over the old one, and allows you to easily work on 6 vials simultaneously. The one upgrade we would like to add in the future is the ability to somehow heat the vials from beneath, to speed up evaporation of high-BP solvents.