Liquid gas techniques for GC trace analysis

Liquid gases (LG), i.e. low boiling compounds with vapor pressures below 5 bar at room temperature, are introduced as solvents for trace analyses. A system for preparin, diluting and handling LG solutions safely and conveniently in 5 to 500 μl amounts was developed as well as a syringe for direct injection of μl-LG samples into capillary GC. Even technical grade LG are of high purity. GC/FID of LG solutions (starting at −60°C) allows the separation of volatile traces from the solvent peak: e.g., dichloromethane can be measured in the picogram range.