: Gas chromatography ( GC) is a method of identifying and quantifying the components of a mixture. This is done on a commercial gas chromatograph instrument. In gas chromatography a carrier gas (usually inert gas or N2) is used as the mobile phase and a column as the stationary phase. The substance to be analyzed is taken in solution and injected into the head of the column with a microsyring. As a result, the solid overhead of the column is overlaid with different dimensions according to the structure of the object. A carrier gas ( He or N2) is then driven through it. The carrier will carry the gas object from the solution and pull it through the column. In this way different objects come out of the column at different speeds which are caught in the form of signal in the detector. The time it takes for each element to reach the emission mouth is called retention time . The capture time and the peak area of the detector signal are used to identify and quantify different components.