ABSTRACT
In Gas Chromatography (GC), the mobile phase is a gas, usually nitrogen, helium, or hydrogen, introduced to the column through a pressure regulator from a cylinder of compressed gas. The general concept of GC was put forward in a Nobel Prize-winning paper by Martin and Synge in 1941 and implemented by James and Martin in 1952 under the name “vapor phase chromatography.” Modern GC instruments can sequentially analyze up to 100 or more liquid samples without manual intervention. Racks or carousels of vials containing liquid samples or standard calibration solution are capped with thin septa, like miniature versions of the GC injector port septum. GC analysis of neat mixtures or highly concentrated solutions may require that only a portion of the sample that is vaporized in the injection port enters the column. Modern capillary GC instruments often feature a split–splitless injector.
