Factors affecting selection of mobile phase in gas Chromatography

Selection of mobile phases markedly affect separation efficiency of eluted probes in gas chromatography (GC), the mobile phases have a pronounced effect on the retention times and efficiency of natural gas separation. In solid chromatography, carrier gases which are adsorbed to any extent occupy more active adsorption sites, reducing the net heat of adsorption of the eluted zone. The efficiency of separation of a light hydrocarbon mixture is shown to depend markedly on the type and pressure of mobile phase in addition to the column temperatures. Hydrogen and helium are the preferred mobile phases in GSC giving higher efficiency of separation because of their higher thermal conductivity. Helium is the best one because of its safety to handle than hydrogen. Nitrogen is the preferred mobile phase used in FID giving high efficiency of heavy components of natural gas separation.